Irfanview can do batch processing, ie. you could convert all 200 pics in one folder in one go.
Once you have downloaded and installed Irfanview, use the Help option to search for "Batch Conversion" to learn how to do the batch conversion.
BTW, when you say " I have a file that contains multiple pics e.g. 200 ", your "file" reference should actually say "folder" or "directory". A "folder" is not a "file" but does contains a number of files. In this case it would be 200 photo files.