Mac 10.7.5 doesn't display pictures properly! Help!!


I use Gimp to create images. When I view those images on my computer (Mac OS 10.7.5), they look great (just like they did in Gimp when I created them). When I look at those images on anyone elses computer... older versions of Mac OS and Windows computers, they look terrible!!! Weird background colours, shadows, and places where I thought I had erased a colour all show up!!

I cannot figure out what to do about it. The only thing I can assume is that my operating system OS 10.7.5 has a problem with the way is shows colour and transparency.

Someone please help!!!! I have created over 200 pictures on my computer and now I don't think I can use them.

Thanks in advance!