When I’m using video as a source material for a recreation, I often use Avidemux. Avidemux will either export .bmp files or .jpg files.
I like to export .bmp files from Avidemux as they are lossless. However, they are also very large and I usually want to convert them to .png files to save space. To do this using a graphics package would be boring, time consuming and prone to error.
To convert all the bmp files in a directory to png files I simply use:
mogrify -format png *.bmp
And then to remove the original bmp files I can use:
And the finished result:
This has saved me literally hours of work over the past few months.