File Upload with RegularExpressionValidator not working with Firefox only IE

Question

I have a FileUpload with a RegularExpressionValidator with the following Validation Expression:

^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))+(.gif|.jpg|.JPG|.JPEG|.GIF|.jpeg|.png|.bmp|.3dm|.3dmf|.ai|.drw|.dxf|.esp|.mng|.png|.ps|.psp|.svg|.tiff)$

This way I make sure the User only upload images. But for some reason it does not work when I use Firefox. Why is that and how can I go around the problem?

Answer 1

Try this:

(.*?)\.(jpg|jpeg|png|gif)$

Answer 2

An enhancement to DaDa's solution that caters for case-sensitivity:

^(.*?)\.(((j|J)(p|P)(e|E)?(g|G))|((p|P)(n|N)(g|G))|((g|G)(i|I)(f|F)))$