There are varying degrees of JPEG compression. I haven't used Irfanview, but most programs I've used (including Photoshop, Paint Shop Pro, and MS Photo Editor) will allow you to vary how much compression you use. In all of those programs, you do a File - Save As (not just Save). Then once JPEG is selected as the file type, there is an Options or Advanced button where you can increase the compression.
How many pictures are we talking here?? 107MB is quite a bit of space.
'98 Camaro SS: Incon twin turbo. Sold
'99 Camaro SS: Heads/cam/bolt-ons. Sold.
'91 Camaro RS: Stock.
2010 Camaro SS: Hell yes.