Convert atk to psd Online: atk2psd

You can use Tom's Editor to easily convert images from
Andrew Toolkit raster object .ATK to Adobe Photoshop .PSD.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

ATK

Andrew Toolkit raster object is an image format with extension ATK.

PSD

PSD is in internal image format of Adobe Photoshop. It can store all the features offered by Photoshop, like layers and paths. Images can be compressed or not.