Image format conversion--The importance of rational use of tools and analysis of common image conversion tools

It is recently necessary to convert files in PNM format into GIF files in bulk. I have tried the following image conversion tools:

Imagebatch: Completely free, but only supports PNG JPEG BMP gif four format

officeconverter: Online conversion software, supporting the conversion of all image formats, a large number of image processing needs to pay a certain fee, otherwise inefficient

pixillion: Support for all formats, the trial version only supports up to 5 files for a set of batch processing, 100 times after use must be paid

Since none of the above tools meet my needs (do not want to use the paid software), I try to search the PNM to GIF file package and find that the Python Imaging Library (PIL) can be installed to convert PNM files to PNG first, Then convert PNG to GIF. But the simplest approach is to use the ImageMagick tool for conversion. Execute the following statement in the Ubuntu Shell:

sudo apt-get install imagemagickmogrify  -format GIF*.PNM

Image format conversion--The importance of rational use of tools and analysis of common image conversion tools