Difference between PE and GIMP in terms of file sizes?

[#1]

I took a file that was 1.3 MB in PE to crop it in GIMP 2.8. I only cropped a very small amount. I wanted the same image quality, so I saved it at 100%. The resulting file was 4.3MB. I tried again and I think GIMP adjusted things automatically because it was set at 93% and the file size was 1.2. But I'm trying to understand how my 1.3MB file could end up a 4.3MB. The 1.3MB file was saved at the "maximum setting" in PE. Thanks.

[#2]

I guess it's a difference on how much compression is applied or lack there of between gimp and elements, however using 100% (12) setting just bloats the file size in both applications and is not recommended. Using a setting of 60 (8) is a much better compromise between quality and file size.

[#3]

Thanks Jeff

[#4]

Was it a JPEG? If so this sort of thing will certainly happen. You have increased quality, I expect, which decreases compression.

[#5]

Thanks Test. Yes, it was a JPEG.