Most images are not meant to be used as wallpapers. Freely available images are either too small or low quality for this purpose. See how to get the most out of what's available with the best tools.
There are many beautiful pictures already
In principle that's correct, but relative to the number of existing images, they represent a very small portion. Do a Google images search for anything and look at the quality and sizes of the results. How many would you like for your background? The answer is most probably none or, if you're lucky, a few.
You could also look at user-rated collections of images. Take deviantart.com for example, it has a large number of pictures (42 million). Their all-time ranking has good images in the top 1 million at most. It means that only approximately 2 percent of the images are worth something. Among them, only a small part have the adequate resolution. So probably less than 1 percent are good wallpapers material.
Still, there are many images to choose from. But, when including the size factor and your personal preference this number decreases a lot.
Fixable image defects
While there theoretically are good quality images that fit your profile finding them is the biggest problem. Because of the large fraction they represent, poor quality images are the most probable result of any search. Many of these are just plain useless, but some of them can be improved.
The most common problems with online pictures are: excessive noise, compression artifacts, wrong focus/blur, over/under exposure, non-fitting color tints, over-sharpening and small size.
Adjusting the adjustable
Photoshop has several features that could come in handy. For each of the defects, here are some solutions:
- Excessive noise: reduce noise filter
- Compression artifacts: reduce noise filter (check the reduce compression artifacts option)
- Inappropriate blur: smart sharpen
- Exposure correction: shadows/highlights adjustments and levelsColor tints: auto-color, levels on color channels.
Why small sizes?
First, images are have low resolution because some of the other defects. How so? Blur and noise disappear when the image is shrunk. Photographers know this, and when posting images on the web they resize them first to look better.
Second, it's because price varies with size. Giving away larger images means giving away more money. This is why professionals tend to stick to very small sizes when putting their work on display. It increases exposure without the risk of somebody inappropriately using their works.
There are other reasons for small sizes like the lower resolution of some displays and the limited space available on web-pages to name just a few.
There are tools for increasing resolution without creating blur and noise. A free site for enlarging images is reshade.com.
Repairing will-be wallpapers
The techniques already presented can be applied to general purpose images. Because desktops have different aspects (the ratio of the width to height is 5/4, 4/3, 8/5 etc) changing from one to another in some cases is problematic. Multiple methods can be used here: cropping, stretching and non-destructive extension.
- Cropping: When an image has a larger aspect ratio and needs to fit on a smaller ratio screen cutting it is a good solution. Just take the part that’s most interesting and leave the rest out. In this case some of its width is removed.
- Stretching: While theoretically no information is lost, the resulting image is often very distorted.
- Non-destructive extension: The idea is to make a crop. But this time try to remove only the parts of the image that are less informative (blurry regions). For more information look for the seam carving algorithm.
Even if you find many great wallpapers there are a lot more you could enjoy with just a little improvement, and maybe a little less effort overall.