What quolity photo to upload ??

What resolution should i upload? I am a little worried that if i upload a smaller file size it will decrease the quolity and look of the photo and will turn people off. So at the moment i have been uploading the full size image which is: 5616 x 3744 - 300ppi
These photos are from 10mb - 22mb a file and take a very long time to upload.
Wondering if there is a better way to do things. Maybe upload a smaller file and only upload the original when the buy it???
Any help with this would be great :)
1 person has
this question