Posts tagged Useful tools

I recently had a large number of bitmaps with magenta backgrounds, you know the old style way of indicating the transparent parts of an icon, that I needed to convert to PNGs with transparency.

I was preparing myself for the serious tedium of converting them by hand, when I thought that there must be another way to do it and fortunately for me, there was: ImageMagick (Wikipedia link).

I had used this open source application before but it was a long time ago and I had forgotten all about it. Luckily a couple of Google searches reminded me about it and, after the usual amount of command-line trial and error, the solution to my problem was this:

mogrify.exe -transparent magenta -format png *.bmp

The documentation gives more details about the options but to summarise:

• -transparent magenta - sets the colour to be considered transparent
• -format png - sets the output file format
• *.bmp - specifies the files to process