Batch optimization of PNGs for iphone/ipad display

Question

I'm working on a magazine viewer for ipad and I'm struggling with the performance.

I figured out that the most expensive part of displaying the pngs is the loading process. I know that xcode is able to optimize pngs during the build and such images are loaded much faster. But I can't include all images in to the build as it will be huge.

Do you know how to optimize an arbitrary png without including it in the build process?

Do you know what is the best format for iphone? I think that pngs should use RGB-8888 color scheme but I'm not sure what else is important.

Maybe you know exact params for imagemagick?

Answer 1

We used Pngcrush to compress huge number of PNGs. You can try this too. And also if you don't need transparency then instead of PNG you can try JPG too. But you may go through a number of trial-and-error process for this, comparing the size and quality trade-off many times.