Multideck 1.7.1 is available - Create custom card decks for prototypes

TL;DR: Multideck is compatible with The Game Crafter, and is designed to be a good tool for creating card images to upload there.

Details:
To prepare a card deck for publication by The Game Crafter, you need to create separate image files for each card face and card back, and then upload them to The Game Crafter's site. Multideck's Export function is designed for this. Exporting will create a folder of suitable card images which you can just upload to TGC.

The output images are in PNG format. For TGC compatibility you should select the 300dpi, "Include Bleed Margin", and "Separate Image Files" options in the Export panel (or just click the "Print on Demand" button, which will accomplish the same thing).

You do not need to use TGC's templates in order to create cards for TGC in Multideck, but you do need to be familiar with the templates. In particular, you should be aware of the bleed and "safe zone" requirements.

Multideck will draw a card outline (the intended "cut" border for your card) in its Layout view while you are designing. But that outline will not appear in the exported images, which will be larger than that outline because they will include the specified "bleed" margin. You may have items such as background art that extend beyond the card outline into the bleed margin in order to guarantee that there is no inadvertent white space at the edges of your printed cards. Multideck also displays a "Safe Border" in this view to help you to place important content where it is guaranteed not to be cut off by registration issues. This is the same border as the dotted blue "safe zone" outline that TheGameCrafter supplies in their templates, and it also will not appear in your printed or exported card images.

In short, you should have no problems. Please do read the built-in Help, which has a section talking in detail about the Export function.

Thanks for your interest!