ssCore.SysTools.getImageInfo is not working for PNG files. For PNG files, it returns null for width and height both. For JPG, its works perfectly.
This is the error description I am getting:
Bad or unrecognized image file format
Yup, that's correct. I created a new Image plugin to get around a similar problem (resizing PNG files) so I'll add support for getting the image dimensions to that plugin for you. Fire off an email to firstname.lastname@example.org and I'll send you the plugin when it's ready.