Excellent for:
- Resizing huge images down to 1920 x 1080 (widescreen).
- Cropping images
- Correcting defects in an image
There are good tutorials as well:
Starting your first "project"
How to resize and crop an image
Image resizing and cropping
Rotate and Flip image (and other things)
Many more tutorials here:
https://www.youtube.com/playlist?list=PLrq_zvwF5agdxDJfxjLp5s16O4_2YbK7d