unclosed blobs

[teekuningas]

Hello! When I was uploading images to our volto 15 site, I sometimes got "Can't commit with opened blobs." errors. Sometimes I also got "ResourceWarning: unclosed file" -warnings to logs.

Fixed it by closing this fd before returning: https://github.com/plone/plone.volto/blob/main/src/plone/volto/scaling.py#L55

Don't know why no one else seems to be affected!

Thanks,
Erkka