One-liner to resize images in current folder

To resize all images in the current folder using ImageMagick from bash shell:

for i in *.jpg; do convert -resize 800x600 $i ${i%%.jpg}_800.jpg; done;

So if you had
a.jpg
b.jpg

you get

a.jpg
a_800.jpg
b.jpg
b_800.jpg

where the *_800.jpg images are resized to 800×600.

Enjoy!