security: making sure graphics uploaded by users are safe

[keiusui]

Hello Monks,

I have written a Perl script for a website. The script accepts an image submitted by the user. The image is then displayed on the user's profile.

Clearly, there are security issues when accepting an image from a user. Here are some of the precautions I have taken:

1. Make sure the image is no larger than 1 megabyte.
2. Make sure the image mime type is jpeg, gif or png.
3. Save the image on the web server under a randomly generated file name.
4. Make sure the dimensions of the image is within an acceptable range of pixels. (I use the Image::Size module to determine the dimensions.)
5. Make sure the user checks the box that says he has permission to upload the file as his image.

My concern is that, even with all those precautions, someone could still embed a virus in the image. How do I prevent this from happening? Should I use a module like Image::Magick to write a new image altogether? Do I need to run a virus check on each submitted image?

Also, are there any other security precautions that I need to take in regards to accepting a user-submitted image?

Thank you so much for your time and help.