I have an image upload on my page and I would like to validate that its actually an image server side after the form submits before I do anything with the image (i.e. actually upload it using <cffile). I know ColdFusion has the <cfimage tag, but I don't know if that would be the right tag to use / how to use that tag to validate an uploaded image.
I know I could use RegEx to check the file extension, but that doesn't stop someone from saving a text file as .jpg and uploading it. Therefore, I'm just looking for some good ol' server side validation for an image.