AnAustralianPhotographer , 4 months ago

Ive downloaded imagemagick and used the convert program to make them smaller.

convert -quality 85 input.jpg output.jpg

should make it smaller, the 85 is a % factor which determines how much compression the algorithm uses. 100% is big files with high quality, the default is something like 92% .

convert -resize 1920x1080 -quality 85 input.jpg output.jpg

also adjusts the resulting image size.

For the image i used, it was 3840*2160 and 3.0 meg. When compressing with 50% quality, the file size was 850kb, when resizing down, it was 250kb,

How much each file size shrinks with % compression will likely depend on what the image is.