The v1.3 model weighs in at 4.3 GB. There's an additional download of 1.6 GB of other models due to usage of huggingface's transformers (only once on startup). And the conda env takes another 6 GBs due to pytorch and cuda.

Larger images will require (much) more than 5.1 GB. In my case, a target resolution of 768x384 (landscape) with a batch size of 1 will max out my 12GB card, an RTX3080Ti.