Yes, Light Image Resizer is also a jpeg compressor tool, it's the purpose of the software. the jpg compression is quite complex to explain, but you just need to know what are the typical value. if you are using 100% it is not a good idea, because the file could be still huge and you won't really see the difference with 99%
actually if you want a quite high quality but save some space on the drive, I would say the best value is 93%

everything around 90% is correct for most users.

if you want to use the compressor at a better level you need to estimate how detailed and complex is the photo, you can try around 85%, below 75% you should start to see some artefact ( like big squares in the edge of shapes in the pictures )

typically with a compression level at 90% you can already save 10 times the value of the original size when it is not compressed at all.

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