There are two main file type errors you may be receiving during upload:
1. ‘Unsupported file type’ error in ESP
There are two things that are likely causing this error in ESP: Either you’ve selected the wrong File Type to upload in ESP, or your JPEG preview doesn’t meet our requirements.
First off, make sure you are selecting the correct file type when you upload. To do so, go to ESP > My Content > Upload & Review Content. Ensure you are selecting ‘iStock Creative Illustration’ as your file type from the drop-down menu on the top left: If you have selected ‘iStock Creative Image’, it will not allow you to upload vector files.
Secondly, once you’ve selected the correct file type, make sure that your JPEG preview is the correct size and is an RGB file. JPEG previews must be saved as RGB at a minimum size of 1900×2800 pixels.
2. ‘This illustration does not appear to be an EPS file’ error message
This is a relatively common error, however it’s not an error from iStock: It’s an error from your web browser.
This most commonly occurs in Firefox (though it can happen in any browser), and it’s called a MIME-Type error.
Basically, what has happened is your browser is no longer able to identify an EPS file.
If this happens, all you need to do is switch to another browser to upload your file. The error message will stop as soon as you switch.