Imagemagick Resize images

# resize image to width 25, keeping aspect ratio
convert -geometry 25x src/image1.png out/image1.png

# resize image to height 25, keeping aspect ratio
convert -geometry x25 src/image1.png out/image1.png

# concatenate images horizontally
convert +append src/image1.png src/image2.png out/image12horiz.png

# concatenate images vertically
convert -append src/image1.png src/image2.png out/image12vert.png

# batch resize jpg files output to same filename with "_small"
mogrify -resize 240 -set filename:name "%t_small.%e" -write "%[filename:name]" *jpg

# optimize image for web, decrease quality
convert input.png -quality 50 output.jpg