A png file raises "cannot write mode RGBA as JPEG" when rendering thumbnail

[piotrgrubicki]

1. Create a screenshot on Mac and save it as png (author: @jpggvilaca )
2. Upload it to Tune's project.

When rendering the thumbnail the app throws an exception:

geti-tune-1  |   File "/application/backend/.venv/lib/python3.13/site-packages/PIL/JpegImagePlugin.py", line 669, in _save
geti-tune-1  |     rawmode = RAWMODE[im.mode]
geti-tune-1  |               │       │  └ <property object at 0x7cc824536b60>
geti-tune-1  |               │       └ <PIL.Image.Image image mode=RGBA size=64x64 at 0x7CC63C151450>
geti-tune-1  |               └ {'1': 'L', 'L': 'L', 'RGB': 'RGB', 'RGBX': 'RGB', 'CMYK': 'CMYK;I', 'YCbCr': 'YCbCr'}
geti-tune-1  |
geti-tune-1  | KeyError: 'RGBA'
[...]
geti-tune-1  |   File "/application/backend/app/api/routers/media.py", line 177, in get_media_thumbnail
geti-tune-1  |     thumbnail.save(buffer, format="JPEG")
geti-tune-1  |     │         │    └ <_io.BytesIO object at 0x7cc8084b0130>
geti-tune-1  |     │         └ <function Image.save at 0x7cc824564180>
geti-tune-1  |     └ <PIL.Image.Image image mode=RGBA size=64x64 at 0x7CC63C151450>
geti-tune-1  |
geti-tune-1  |   File "/application/backend/.venv/lib/python3.13/site-packages/PIL/Image.py", line 2590, in save
geti-tune-1  |     save_handler(self, fp, filename)
geti-tune-1  |     │            │     │   └ ''
geti-tune-1  |     │            │     └ <_io.BytesIO object at 0x7cc8084b0130>
geti-tune-1  |     │            └ <PIL.Image.Image image mode=RGBA size=64x64 at 0x7CC63C151450>
geti-tune-1  |     └ <function _save at 0x7cc808692980>
geti-tune-1  |   File "/application/backend/.venv/lib/python3.13/site-packages/PIL/JpegImagePlugin.py", line 672, in _save
geti-tune-1  |     raise OSError(msg) from e
geti-tune-1  |                   └ 'cannot write mode RGBA as JPEG'
geti-tune-1  |
geti-tune-1  | OSError: cannot write mode RGBA as JPEG

The culprit attached.