I frequently get asked how to make a small image larger - meaning that
someone has found an image on the internet (typically a thumbnail of some sort)
and want to enlarge it to something bigger.
Unfortunately, image detail that was lost when the image was resized to be
smaller cannot be recovered by resizing it larger again.
In this video excerpt from a recent Ask Leo! webinar on
photo manipulation, I'll discuss what it all means.
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Transcript
So one of the other questions that I often get is people want to take an image that they found on the web (commonly the scenario) and make it bigger. The image is too small; they want to basically enlarge it so that they could perhaps see more of the details in that image.
What I'm going to walk through here is exactly a) how you would do that, but b) why you're not going to be happy with the results. So the image that I'm going to use is a familiar one, I hope, to all of you and that is the logo from my website. That image is 78 pixels high, it's 260 pixels wide, and it is obviously a photograph of my face.
So let's say that for some reason you wanted that photograph, only larger. You don't have the original, all you have is this that was taken from a website somewhere. Yes, it is absolutely possible to use the resize function in an image editor (such as FastStone) to say, "Let's make that image 400% bigger." So we're going to take the original 260 x 78 image and make it 1040 x 312. It'll be bigger; absolutely, it'll be bigger!
The problem is it won't be any clearer. The problem is that when an image is resized, information about that image is lost in the process. The information that contains all of the details of the actual thing that you're looking at (at the resolution that it was originally shot at) is removed; that's how you make the picture smaller. When you enlarge the small picture and make it larger, there's no way to add that information back in. What happens instead is that the existing low resolution information is simply expanded to fill the space. So, as you can see, my face here is actually pretty blurry. In fact, I'll make it even larger; I'll make it even larger since there's an opportunity here. I'm gonna go for 800%. So now, you can see ... no, we're actually scaled so I'm going to go to (let's see, I should be able to hit 'View' ) what I'm trying to get it to do is to view it at 100% - there we go, 100%. So, this is the original picture; my little 72-pixel high headshot expanded to be 624 pixels high and as you can see, it's really blurry. The information that was present in the original got lost when that original was scaled down to 72 pixels and there was no way to add that back in.
Now, what most programs do and I have to admit that FastStone has done a very nice job of this is they apply smoothing algorithms, so that they're not just giving you 72 pixels where each pixel is now like eight pixels in size or something like that. They actually take a look at the colors and what's being shown in the image to provide a smoother result than just making each pixel bigger. So actually, it's blurry; it's definitely blurry, but it's actually not bad for having been increased 800%.
So unfortunately, what that means though is what you're trying to do (by taking a small picture that you find somewhere and increase its size to whatever to enlarge it) to be able to see the details that you can't see when it's small is doomed to failure because those details aren't there in the first place. What resizing does - it's interesting because when you take a look at a picture like this, you say, "Oh my gosh, it's blurry. I would never want to use that." But on the other hand, if you take a look at the original, it seems like it's a lot better, it seems like it's sharper; it's not. It's an optical illusion. It is the fact that your eyes perceive this to be a smaller picture; it looks like it's better. As soon as you expand this to fill a larger area, you can now also see imperfections that were in the original photograph.
Gosh Leo, but those guys on CSI do it all the time and it looks great!
13-Apr-2012
Just like the old Sunday comics pages where you look at them with a magnifying glass and you can actually see the individual ink color dots. That was also the problem with enlarging film photos; they’d just get grainier.
In electronic video, there is a function called Sharpening. Notice how, in a drawing when you add shadowing, it appears to add ‘sharpness’ by creating more of a 3D effect? That’s what video sharpening does; it adds drop-shadowing. It appears to enhance the detail, but really it’s just adding ‘noise’ to the video. Your eye PERCEIVES it as an improvement because it’s pleasing, not because it’s accurate.
Which is why it helps on shows like CSI, because it provides visualization the eye, alone, can’t imagine in order to expand guesswork. But not admissible in court because it’s not real. And it’s also not limitless. Too much video sharpening just looks like double or triple imaging.
If the photo is a smaller version of something that *is* published on the Internet, you may be able to find the original using something like TinEye or Google’s Image Search. The Google search is amazing and finds similar photos to the one you provide. I have used it a number of times to find the best version of something.
Something else you can do if you want a larger image is to find it on the internet. If you go to http://www.tineye.com, you can browse the web to find an image’s origin. After you upload your image at this website, the site will tell you where it came from, whether it’s been Photoshopped, and where higher-resolution versions can be found. The first 50 searches a day are free. (Information is published from PC World – April 2012 edition on page 73)
I’m 74 and the old eyes are as sharp as they used to be. So when I’m looking at photos on the internet I keep a copy of ‘xnview’ on my rail. I just right click the image and then bring up xnview and ‘display clipboard’ Then I can hit the plus button to enlarge it. If I want to save it I just hit save as.
I’m 74, too, and I’ve discovered that a smallish image or photo can be inserted and resized in a blank Office 2007 Word document, up to a full page, depending on the dimensions, without losing quality. All you have to do is click on the image, once it is inserted, to get handles around it, and use the lower right corner handle to pull it out as far as you want it, or to the margin(s). The document can then be saved as a *.doc file. I have made full page portraits this way and printed them on photo paper. They are not blurry at all.