So you are downloading the images from Twitch and storing them on your database?
If I’m displaying profile images usually what ill do is create an image tag and set the source directly to the image on Twitch servers.
Also, if I’m not mistaken, you can’t hold a Twitch users data on your database for more than 24 hours, in this case their profile image.
Source: http://www.twitch.tv/user/legal?page=api_terms_of_service (See 12.c)
Hope this helps!
Kakeiso