Sometimes Pinta or eclipse throws an error while opening the png file from the eclipse via Pinta, in such case you can use one of the following options to open the png file in the pinta.

Option 1: Open Pinta first, then click file, and open. Navigate to your CodaKid folder, then inside projects, then the project name, then src, then main, then resources, then assets, then foundations, then textures, then items.