Upload of faces fails a lot

[Tokn59]

When trying to upload (Add a face) in Frigate 16 I mostly get a "red cross" next to the pictures and no error message is given. In the example I use a PNG picture with a resolution of 605 X 663 ixels, 72 dpi and a filesize of 507 KB. I tries with a larger size of the same picture 1080 X 1920, 749 KB size, 72k dpi) but all fail. Why is this and what should a valid format be ?

[NickM-27]

The red x is there to just remove the image if you want to try a different one

[Tokn59]

Sorry my mistake but I clicked on "Next" several times without result so I thought the image was invalid.