Q: Slow running Ipad

If you're able to, I recommend doing the backup to iTunes (just in case); then Restore, using that backup. One possible issue is that your backup may need more space than your iCloud storage plan has.

This article has some useful info in it:

https://support.apple.com/en-gb/HT204136

Backup with iTunes like nick101 said above. All the pictures in Camera Roll will be backed up as well, they should not go away but I am one of those that believes in safety - before you do a Restore, import all your pictures to your computer independently of iCloud or iTunes. You will then have a complete set of pictures on your computer that you can view there as well (you cannot view the pictures in a backup). Here is how to import your pictures:

Import photos and videos from your iPhone, iPad, or iPod touch to your Mac or Windows PC - Apple Support

And here is how to do the Restore just in case:

Use iTunes to restore your iPhone, iPad, or iPod to factory settings - Apple Support