Use ffmpeg to resize image

Solution 1:

You can try this:

ffmpeg -i input.jpg -vf scale=320:240 output_320x240.png

I got this from source

Note: The scale filter can also automatically calculate a dimension while preserving the aspect ratio: scale=320:-1, or scale=-1:240

Solution 2:

If you want to retain aspect ratio you can do -

./ffmpeg -i 1.jpg -vf scale="360:-1" 2.jpg

or if you want to resize based on input width and height, let's say half of input width and height you can do -

./ffmpeg -i 1.jpg -vf scale="iw/1:ih/2" 2.jpg

where

iw: input width
ih: input height

Solution 3:

It is also possible to resize an image to fit inside some dimensions and letterbox the rest.

Example command:

ffmpeg -i IN.png -vf "scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2" OUT.jpg

See this answer for more details.