So you have tons and tons of pictures and you want them all to be the same format and size. Or you just want to convert some of your photos.

Enter "convert".

Convert is exactly what its name implies. A converter... For images and drawings. Convert works on all sorts of images types and even works on layered drawings.
And since convert is a console app you can insert it into your batch files and cron scripts to do automated conversion processes.

For more information: man convert

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