With the high resolutions of many of todayās digital cameras and phones, the
files that contain our photographs can end up being quite large. So large, in
fact, that it can be a problem ā either to store or share with others.
In this video from an Ask Leo! webinar on
Photo Manipulation, Iāll show a couple of techniques to make large images
physically smaller ā including one that even keeps it the same visual
size.
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Images referenced
Transcript
We will move on to making files smaller in terms of file size. One of the common problems I hear about on AskLeo! are people who are attempting to mail photographs from one to another; share photographs via email and have the email bounce because the photographs themselves are so large. Their mail system happens to have some kind of a problem with the size of an email.
So, in this particular case, what weāre going to do is take a look at a photograph and take a look at some of the different ways that a photograph can be manipulated in order to make it smaller; not necessarily in terms of its physical size, its visual size (although weāll look at that, too), but in terms of its actual file size.
So, this particular photograph (and Iām actually going to change the display here) you can see that this particular photograph that I took earlier this year ā itās a jpg file; itās 4288 x 2848; that is the raw dimension, the full size, as it comes off of my camera and you can see that it is roughly two megabytes in size. Now, two megabytes isnāt a particularly large attachment, but in some cases, it can be. And in particular, if youāre sending several photographs, two megabytes adds up pretty quickly. I know of email systems that have as low as five or ten megabytes email attachment limits, in which case, adding just a couple of photographs could easily cause you to trip into a scenario where your email would bounce for being too large.
So, letās go ahead and take a look at that photograph first ā full screen ā here it is. So, the first approach to making the file physically smaller; in other words, Iām talking about not visually, but the file size on disk to take that two megbyte file size and make it something smaller than two megbyte is to play with the jpg compression setting. So, what does that mean? What Iāve done here is so far Iāve simply started to do a File > Save As. In other words, Iām going to save a copy of this photograph. One thing thatās always important to realize is that you should never, ever save on top of your original because once your original has been overwritten by your edits, you can never go back. Typically, your original has the highest fidelity; the original āpreā any changes, you just want to make sure you always give your changed files, your changed images, a new file name so as to preserve the original.
So, in this particular case, Iām going to go ahead and give this a slightly different name. And youāll see why I say āqualityā here in a minute. What weāre looking for is this item down here ā jpeg quality. Letās go ahead and have a look at this. The jpg image compression format and it is an image compression format has an adjustment that adjustment letās you trade off file size for picture quality. So at one extreme, we have the highest quality possible here and what weāre seeing is before and after saving the file are pretty much the same ā theyāre visually identical. What Iām going to do is take the quality bar and move it down to the far end. Iām going to go ahead and give this zero as quality. So what Iāve done at this magnification. One of the differences that you can see at this very low quality ⦠here we go, letās use 11 here as the quality because you can see visually some of the changes that have occurred to the picture.
Before, the picture looks as you might expect: very gradient; the color here is very smooth; the contours of the grass here look appropriate, in fact, weāll zoom in here in just a second. As you can see, with this lower quality of 11, all of a sudden the gradient of the sky has turned into something extremely visible; very āsteppyā. You can take a look at the actual blades of grass that have now become very āpixelatedā is one way to describe this. Pixelated and/or showing what are called ājpeg artifactsā thatās a lot what these blocks running around the middle of this, otherwise, solid color.
So the bad news is that the picture looks worse than it did before. Depending on the type of picture, that may or may not matter to you. If your picture is more like the bottom half of this picture, then it may not matter that it is of low quality. If youāre looking to preserve whatās above, like say the gradient in the sky, then this low quality could in fact be a significant obstacle.
But the good news is take a look at the different file sizes. The original file size for this picture was two megabytes. This is now under 100K, so if I go back to the entire photograph ⦠now you can do a nice side-by-side comparison of exactly what the difference means. You can send this one as two megabytes or you can send this one that has under a 100K.
Now, exactly how those changes get reflected in different programs and in fact, the math behind the different quality settings may vary from program to program. Take this up to something like 91 and youāll see why Iām doing that here in a second. So, itās one of those things that youāll want to play with if you ever encounter this situation. But one of the things thatās worth looking at is just off of perfect quality. So, itās currently set to 91 out of a possible quality of 100. And again, for the record, the numbers that are used may very well differ from program to program. FastStone is using a scale of zero to 100; I have seen ālow, medium, and highā; I have seen ā1 through 10ā but the idea is that somewhere, there is a slider; a choice; a way of defining what kind of quality you want to preserve in your image when you save it in jpg format.
So when we return this and we go back to this and say quality 91, the file size is (gosh) less than half of what it used to be, but itās already under a megabyte and yet, it looks pretty darned good. In fact, Iād have to be looking at it very closely in order to understand what, just exactly what, if any, difference it made. Thatās why I point this out ā because for a small change in saved quality, you can end up with a significant decrease in file size that nobody will ever care about.
The neat thing about jpeg compression is not that itās this wonderful mathematical way of compressing images, although it is. What it is, is a format that understands how people look at images and uses that to degrade the quality gracefully to maximize what you see as opposed to exactly how the bits are stored. One thing to point out (and it should be obvious by now given the types of things weāve done to this photo) jpeg is what is called a ālosseeā compression. In other words, the more you compress it, the lower the quality you choose the more data that gets lost from the image. You end up with these artifacts; you end up with various pieces of information that describe the photo being ālostā in exchange for the smaller file size. But obviously for photographs, itās a very efficient approach to saving images, specifically images in as small as a file size as is reasonable.
So what Iām going to do here is Iām going to save this as 91, with quality 91. And Iāll go ahead and change the file name to once again indicate that I have set it to 91. And if we now go back and take a look at the two files, youāll see here that we have two images; theyāre both jpegs; the dimensions are exactly the same. We have not changed the visual scope of this picture at all. It is still exactly the same physical size when you look at it, but the file sizes are dramatically different. And thatās a very simple change that you can make by saving it in a lower quality jpg format.
Letās take a look at the other approach to dealing with size. Iām going to go ahead and exit and re-enter FastStone to make sure that Iām working on the correct original as I expected. What Iām going to do this time is what most people think of when they think of making a picture smaller and that is Iām going to crop it. Now, Iāve talked about cropping in a different segment and sometimes you can do that for some very nice āartsyā effects for example, and in this particular case, the result here of having the sunset and the person juxtaposed with the light. I think, personally, I like this cropped approach to the photo better. So Iām going to crop it. Now, if I just save it (by the way, I right-clicked on the photo this time. Itās the moral equivalent of heading over to the left-hand menu, left-hand edge of the photo where this menu pops up), but Iām just going to go ahead and right-click Save As. And this time, Iām going to call it sunset_cropped and youāll notice that the quality is still at 100, so weāre looking at the exact same quality that we started with but a smaller, literally a smaller visual picture. Now when I go back and take a look at them, you can see that the cropped photo, which Iād say is less than half, actually less than a quarter, of the size of the total surface area of the original is actually not that much smaller than the original.
So my point here is simply that cropping a photo, depending on the complexity of the image within it, may or may not get you the file size reduction that youāre looking for. The data thatās in a jpg file is all about encoding what the image looks like and that can be or actually that does depend directly on the complexity of the actual image thatās contained therein. For example, when I cropped this photo, I cropped off a bunch of essentially solid black that was on the bottom. A big area of solid black doesnāt take that much in jpg to store it. The complexity of the image actually is remaining in the piece that Iāve kept. Itās the person; itās the grass; itās the gradient of the sky; itās the light. So the information that is required to represent that photo even though itās less than a quarter size of the original, a quarter visual size of the original is still fairly high. Thatās why I say often a combination both of cropping (if youāre looking for a visual effect) and then adjusting the jpg size, or jpg quality, are typically the ways to go.
So, I think Iāve gone on enough about this off the top of my head. Letās take a look at questions; I see that there are a couple in and if you have questions about jpg quality and formatting, by all means, now is the time to ask those.
I was wondering if you insert an image, say 1650 x 1275, into the body of an email as a .png, and then resize it by dragging the sides of the picture, will the resized image appear in the recipientās email? Unfortunately, thatās not something that I can answer because that actually depends explicitly on the email program that you happen to be using. Now, Iām going to run off with one example because I happen to know how it works ā Word, Microsoft Word allows you to drag and drop pictures into your documents. What is preserved in the document is the original file. The image itself is not modified. In other words, if youāve got this huge 4K by 2K image and you drop it into a Word document, no matter how you scale the image in the document, in other words, if you drag it to make it bigger or drag it to make it smaller, the entire image is still there. Word is actually adjusting the display of that image when itās displayed, not when itās placed in the document. Since Outlook in the past has used Word as its email editor, and I believe whatever Outlook is doing these days, I believe that theyāve dropped Word, but theyāve got something equivalently complex behind the scenes right now. I believe that would do the same thing. You may scale the image all that you want in the email message, but itās the original file thatās been dropped into the email message to begin with. Now, what does the recipient see is the other half of that question and once again, we canāt really even give you a straight answer on that because it depends on what email program the recipient is using. Typically, and I say this on average, theyāll get what you send them. If what you see when you hit āSendā is a scaled or cropped or whatever image, then typically, the recipient will see the same thing; theyāll see what you sent. But itās definitely not guaranteed. Images, emailing images as attachments are simple; embedded in an email are not. And by that I mean that when you embed an image in an email in the flow of your text, what happens then, I almost want to say itās a crap shoot because the combination of email formats and email programs often render images, they often end up coming out other than you expected. Sometimes, theyāll show up as attachments; sometimes, theyāll show up as the original image, a very common question that I get is that people canāt see them at all except unless they forward the mail; it gets very complicated so thatās why I canāt give you a straight answer. Iām really sorry that I canāt. I wish that it were simpler when it comes to sending pictures like that. My recommendation for sending pictures, in other words, the approach that I suggest in general, for sending pictures from one person to another via email is not to drop the image into the body of your message. It may look pretty, but in fact, it reduces the probability that youāre recipient can see it. Now, once youāve actually confirmed that the particular recipient is seeing what youāre sending, then fine, go for it, have a good time with it. But if youāre not sure, if youāre ever not sure, the only scenario that I know that is most likely to work is to attach photographs as attachments to your email. In other words, donāt put them in the body, but use your email programās attachment function to then attach the specific jpg or whatever to the email and send that. But it doesnāt meant that recipient may have to specifically open the attachments in order to view the picture. Depending on their email program, they may be able to scroll below the body of your message in order to see the images. But it is the most reliable way of getting an image from point A to point B via email. Ah letās see, another question.
Iām not familiar with FastStone. Please compare FastStone with other viewer programs. Is it free? Ah yes, itās absolutely free. And what Iāll do instead of actually answering that question here is directing you to ⦠in fact, Iāll just bring it up right now. I actually did one of these webinars on FastStone specifically so I have two articles that Iād like to direct you to. One is this one which is basically my formal recommendation of FastStone Image Viewer that basically walks through some of its features and gives you the download link. The other one that I suspect may also be interesting to you is this; this is a segment from a previous webinar and you can see in fact, I use the same picture that basically walks through using FastStone for some of the other, many of the things you might want to do with it. So Iāll direct you to those two and as you can see, all I really did was go to my search and search for FastStone and those two came up as the top two search results.
http://www.Irfanview.com also is free, very versatile, and very easy to use for re-sizing and just about anything else, photos and videos.
i have a program, hypersnap, from hyperionics.
i take large photoās, 4000 x 3000, etc.
if we do a wedding, I use BULK RENAME (another utiity) to rename my pictures, appended with _ORIGINAL
Then, with hyperionics, I do a conversion of all images, through a batch utility they have, to rescale all images to about 80% of their original resolution (this is not cropping, but changing resolution)
I name these scaled image as a NEW image, PREFIXED with the word āscaled_ā.
so, now I have both SCALED and ORIGINAL images.
if I scale them to 80% of their original size, this markedly reduces the file size, yet still keeps a great picture.
Now, I then review all the pictures, and any photoās that I would want to keep as a portrait, etc, I KEEP the ORIGINAL version, and then delete all the other ORIGINALS
I then have all these in a folder, with portrait-quality ORIGINALS, and then all the other SCALED ones.
you can adjust how much you rescale these, etc, but this does help to shrink the file sizes
hope this is of benefit ot others
nick
I do a lot of file transfer-type stuff and publish various email newsletters and Iāve found the best tool for me is Shrink Pic. Itās free and does a wonderful job of reducing the photoās file size while keeping the image completely intact.
I think saving as png files would indeed reduce the file size noticeably but that is not true for all cases.
A better option that I have encountered is to zip them all up. It does reduce the file size upto ~50% & if they are vector files, then the results can end up with around 99% compression ratios.
But zipping ā unzipping adds an extra layer of work.
But we are talking photographs out here & I guess Leo showed us the best way to deal with them.
If only for email / web publishing photos in small file sizes and / or dimensions tend to be the best.
Ravi.
28-Jan-2012
I have used Microsoft Picture It 7.0 for years.
It is free and you can āfixā levels, brightness, contrast, color-tint and resizing.
Simple and easy to use.
In my ātrainingāphaseā I used ācopies of photosā just in case I made a mistake.
You can change/choose the desired format.
Deano
In reply to my earlier comment, zipping does increase the file size in case of photographs but just in case they are illustrations, for clip art, for cartoons, for drawings, for anything that involves basically solid colors, then zipping will definitely compress them. Just for your kind information, I have included a zip file sample that shows the same. You can download it from http://www.mediafire.com/?gjwrwv5b3aqtqtz
Thanks,
Ravi.
Thank you Leo for your interesting newsletters. There is so much for me to learn. I am self taught, so still need lots of help. I now use Fast Stone Image Viewer and LOVE it. Thank you. I am a bit uncertain about changing too much until I read a lot more of your helpful tips. I use Norton 360 Version 5 at moment and Love it. Never causes me a problem. I save all your tips in a file so I can read at my leisure when I need to know something. Take Care and kkep the great tips coming thank you.