My question is regarding duplicate title tags.

Alistair Lattimore: Summer, You won`t be penalised for having duplicate titles, however you`d be better of try and make them unique such as "{username} images - Page {x}" so that every page has a unique title tag. Since your site is going to be thin on `content` that Google can index, I`d also be looking for a mechanism to keep the number of indexed URLs to a minimum. You might consider applying meta noindex tags to user profile pages who have uploaded less than a certain number of images or who haven`t filled out their profile information - once they pass a threshold the meta noindex tag is removed. Following in the same idea as above, you might consider implementing a `view all` page for users who have less than a certain number of images. Once the user has uploaded more than that threshold, your site removes the `view all` configuration and reverts to indexing the standard paginated URLs. For the paginated URLs, I would also investigate adding rel="prev"/rel="next tags on your paginated URLs to help Google understand that they are related to one another. You can find out about `view all` and rel="prev"/rel="next" pagination tagging at https://support.google.com/webmasters/answer/1663744?hl=en I`d look into extracting out the photo EXIF data if you can and trying to leverage that in your content in some way, such as the camera used, aperture, shutter speed, longitude/latitude and so forth. I`d also ask your users to describe the image if they can, then use that information on the page or in the alt tag for the images - anything to try and get content from your users and onto your pages. Hope that helps, Al.

Summer Brooks: My question is regarding duplicate title tags.
I have an image sharing website so a user could have say 10 pages of images. ;
At the moment each page of images for each user has the title 'images by {username}'
Is it okay to do this or will I be penalized for having duplicate title tags?

Thanks
Summer

William Gomes: You wont be "penalised" for this but a way to optimise his would be by probably having part of the image description or if it has none the image name in the URL. 

Andy Forgrieve: You could also add page 1 of 10, page 2 of 10 etc to differentiate. Also biggest recommendation is to add canonical tag on each page pointing to the main page. Then search engine knows they are all similar.