optimize PNG Image for Web Sites

[linjuming]

i use the png files for css backgrounds.
i use the faststone phpoto resizer which can optimize a png file from 2M to 465k . the optimized png looks the same as the old one.
can IM do it ? no lossing optimizing ?
can you good guys print out your IM code for png optimizing ? primarily for css background.

[anthony]

IM saves PNG images, bt does nto do a lot of optimizing. It will for example switch between Indexed, 24bit and 32 bit PNG images.

If you want PNG optimization I suggest you use an proper PNG optimizer
http://www.imagemagick.org/Usage/formats/#png_non-im

[linjuming]

Thanks,best wish

[glennrp]

You can try writing to the PNG8 (PNG sub-format).

With IM-6.6.7-10, this will reduce the colors to less than 256
if necessary, using a quick-and-dirty reduction to a 3-3-2
pallette. This is of course a lossy operation.

With earlier versions this probably won't work.

If you don't like that result you will have to use the "-colors 255"
option (for better color quantization) before writing the image.

../glennrp