Originally Posted by nrapallo
I reduced any image greater than 200x??? so that the short side was 200 using IrfanView and didn't enlarge smaller pictures nor used any dithering. For .gifs and .pngs, I just reduced the colours to 16 (4 bit) while with .jpgs I had better luck reducing the Quality to 70 than changing those images to .png or .gif! Any images less than 200x???, I didn't change the size, but did change the colours as above.
For such a large quantity of images, it may be easier to use http://www.imagemagick.org/script/convert.php
as it can be run from a batch file to -resize
or change colour -depth
of large numbers of images at once.
Wikipedia's server-side MediaWiki software invokes ImageMagick's free convert
utility as one commonly-used means to generate thumbnails from uploaded photos for use on content pages; it won't convert .SVG to other formats but will do just about anything else.