ShortPixel backups are one of the biggest culprits of used disk space on your server. These backup folders contain the original, unoptimized images that ShortPixel saves just in case you don't like the results and need to revert. Although they're not used on your live site, the backups themselves can take up many GB of space.
Although the backups are a good idea the first time you run ShortPixel (just to be sure you're happy with the results), they're not necessary in the long term, especially if you also have copies of the originals on your computer.
You can clear out the backups folder by going into Settings → ShortPixel. Click on the Statistics tab, and then the Empty backups button. This will immediately clear out all of the space you're using with those backups and get you back on track, storage-wise!
If you'd like to keep the backups on your server, shoot us an email and we can give you a quote for increasing your disk space. It will just take about three minutes to resize that, during which time your site would be offline, but we're happy to do it after-hours to minimize the impact on you and your readers.
Moving forward, you have two options:
1. You can periodically clear out your backups folder following the steps above.
2. Or you can configure ShortPixel to not save a backup copy of your images. This is a little riskier in that you won't ever have a backup copy on the server and might need to re-upload an image if ShortPixel has a problem optimizing it. But that risk is pretty low. To turn off the back up, click on the General tab and uncheck the Save and keep a backup of your original images in a separate folder button.