I'm not sure that I buy it. The Vita manual specifically recommends that you match the resolution of the image to the screen image for optimal clarity, so clearly someone did think that quality mattered to someone. It would make no sense to do that if the Vita was going to change the resolution needlessly anyway. If the resolution was not going to be changed, then the only thing determining the file size is the color depth; and there are more efficient ways to flatten the palette then to use JPEG compression. Plus why bother to convert five other image formats to JPEG, when the Vita System already has code to render them? I would like to see the source of that information.
Just export the image as a .jpg on your computer. Smaller file size will help. It is because the vita has to store the image on the on board memory unit. That being inaccessable to the user and very small. The images probably get compressed anywhere between the 500 - 1000kb mark.
I may be late to this forum but I even took a screenshot of an image that I wanted to use, but it still ended up looking like crap. Not as bad as just using the image straight-up but the compression artifacts are still clearly noticable once it's made into a background.
I don't care if it's in the internal memory, I just wish that it would use the image file straight from the memory card. So far, this is my second least favorite thing about the Vita.
You'd have to create 3 different buffer zones with up to the maximum amount of data per zone. So, if you wanted the pictures to be up to 6MB, you have to reserve 18MB to avoid problems. No ands, ifs, or buts. The Vita has 512 memory to begin with, so depending on how games utilize memory and how much other memory the Live Area uses, that may or may not be a problem.
Even the PS3 fades to black when switching between application backgrounds. Likely because they use one buffer and empty/refill it on the fly.