Problem with Images

When uploading an image to a product, I get the following error

Warning: imagecreatefrompng () [function.imagecreatefrompng]: '/ home/maquisfa/public_html/media/com_hikashop/upload/flb5_1783373103.png' is not a valid PNG file in / home / maquisfa / public_html / administrator / components / com_hikashop / helpers / image.php on line 738

And the error debabo pictured.

You know what happens?

The problem seems to come from your png file, can you try with another file ?
Maybe this is a picture which had been renamed (extension changed) so the mime type is not correct.