External Image Security

Question

I've got a function on a site that searches Wikipedia for images that are relevant to something a user has put in a text box. If it finds anything it'll download the image and serve it up via a resizing function that looks like

http://mysite.com/image/resize/?w=x&h=x

Is there anything that I should be concerned about?

Answer 1

They might put a huge amount of load on your server by entering massive numbers for x and y. You'd better restrict the dimensions and you should probably do some sort of caching on this. A malicious user could flood your site with requests and force it to download lots of images, flooding it's downward bandwidth.

If you read the wikipedia guidelines, hotlinking is actually allowed , you might be better off passing them through the URL you get from Wikipedia.