I am trying to resize an image with width around 6000 to 7000 pixels, but the file size is low (less than 3.8Mb). When I pass such huge images to image_resize function its not resized. Any ideas on this? Wp version 3.5.
Operations on images are more restricted by the required and available memory than by the file size. The bigger the image is, the more memory it will require in order for it to be manipulated (to be manipulated the relevant libraries usually create a bit map image in the memory so your image will take width*height bytes of memory).