Converting graphics?

[ffutures]

I've been trying to work out the best way to handle the Army and Navy Stores files without losing resolution or messing up the images. I suddenly realised that out of habit I've saved them all with 256 grey scales, but there is no apparent loss of quality at 16 grey scales and files are less than half the size.

Given the number of files I really don't want to load them, reduce the number of colours, and save them again manually. Can anyone recommend a program (preferably for Windows) that'll do this for all the gif files in a directory?

Now sorted, thanks to nojay who recced Irfanview Files have been converted and uploaded already, really can't see any difference except speed is better and less space is used.

Comments

[nojay.livejournal.com]

Have a look at the batch conversion option in Irfanview (keyboard shortcut "b"). It's powerful, cryptic and dangerous like all good software should be... Copy the original gifs into a separate directory for safety's sake, select "use advanced options" and click the advanced button to bring up the "Destroy all Monsters^WFiles!" screen. Top of the middle column sets specific colour depth including 16 colours (4 BPP) for output after conversion.

The main screen allows you to import specific files, all of a given type or even from a list of named files in a text file, and then specify where the resulting files will be output to. Should do the job.

[ffutures.livejournal.com]

Thanks - worked perfectly!

Halved the size on disk, and I can't see any loss of quality.

[armb.livejournal.com]

http://en.wikipedia.org/wiki/Netpbm (but I suspect that Irfanview will be easier).

[ffutures.livejournal.com]

Irvanview worked fine - thanks anyway.