Function: Create new GD image resource with transparency support

Function: Based on a supplied width/height example, return the biggest possible dimensions based on the max width/height.

Function: Determines the maximum upload size allowed in php.ini.

Function: Returns a WP_Image_Editor instance and loads file into it.

Function: Tests whether there is an editor that supports a given mime type or methods.

Function: Displays previous image link that has the same post parent.

Function: Displays next image link that has the same post parent.

Function: Displays next or previous image link that has the same post parent.