Enhancement: balancing image quality of compressed PDFs

[nguyenhung]

First of all, thank you so much for this project. This is helpful because I have to compress a lot of PDFs and upload them to a government portal. I use ilovepdf[dot]com for non-confidential documents. The tool there is easy to use. The quality of the exported files and the file size are perfectly balanced.

I think a dropdown box in "compress PDF" to choose the "image quality" would be great, and the default should be set to balanced.

ilovepdf[dot]com is above: 233KB from 2.5MB web-pdf-toolbox is below: 61KB from 2.5MB

I am fine with anything less than 300-400 KB