[BUG] After importing Contacts from a V 3.0 VCF file, contact images vanish

Hello people

I found an interesting bug (?) of calendar.
I was trying to import contacts from a VCF file (exported by evolution).

During the import phase, I do see the images of the contacts to be available. Even more, if I click on the contact, the photo is here.

BUT if I refresh the page, the photo is gone!

If I export the contacts, the photo is inside the exported VCF file. Even if I use thunderbird with CardDAV, the photo is still there.

Back to NextCloud, the photo is gone!

As a reference I attach here a 1-person VCF file as a minimum example.

Note: this issue is different from [Bug][Help] VCARD V3.0 Photos - #2 by nickelnoff since the photos here are embedded inside the VCARD and not as external URLs. This is the reason why I exported through Evolution, to get the actual photo inside the vcf file.

URL of the demo VCF:

After some more test, I found that if I use CardDav of NextCloud inside Thunderbird (which I remind you it is possible to see photos), and create an entry with a new photo, when I go back to NextCloud, the photo is still not preset, but if I export it, the photo is here.

Could it be that this is a bug of displaying photos?
Should I report it to github of contacts for NextCloud?

I have no idea about your issue. In my instance I have hundreds of contacts (majority imported with vcf from Outlook export), dozens have pictures and I see this pictures everywhere - in Nextcloud UI, Thunderbird and mobile with DavX5

So for me the problem seems to be mainly on stock Nextcloud UI contacts plugin.
Any hints how to debug & see what’s probably missing/wrong?

Also experiencing loss of images in contacts in the Nextcloud web app. They are present in Thunderbird, and in my phone contacts, which both sync with nextcloud. However in the web app, there is nothing. If you open developer tools, console, there are hundreds of 404 URLs as the images fail to load.
I don’t think its anything to do with vcf 3.0 in particular. It just seems to be something which broke in a recent upgrade. All was looking good last time I looked in the Contacts app a month ago. Since then we’ve had a couple of upgrades, so I don’t know which one broke it.

Just adding some relevant info to this …
When a contact image fails to load, the server registers a 404 with a URL similar to this:
/remote.php/dav/addressbooks/users/name/contacts/ADBA8047-F78D-4C50-9206-4BF1E6FEC2BE.vcf?photo

On the question of Vcard versions, my phone and computer all claim to have V4.0 vcfs. But Nextcloud seems to only deal with v3.0 vcfs. i.e. as I understand it, when you upload v4.0 vcfs, nextcloud contacts understands them and converts them to v3.0, which it uses as its working format.
Wikipedia lists these as the alternate formats for the PHOTO field in vcards.

3.0 : `PHOTO;TYPE=JPEG;VALUE=URI:http://example.com/photo.jpg`
3.0 : `PHOTO;TYPE=JPEG;ENCODING=b:[base64-data]`
4.0 : `PHOTO;MEDIATYPE=image/jpeg:http://example.com/photo.jpg`
4.0 : `PHOTO;ENCODING=BASE64;TYPE=JPEG:[base64-data]`

I was hoping to see if changing the format of a vcf on the server might correct the problem, but as the carddata field is a BLOB (don’t remember it being BLOB before when I looked), I’ve run into a stone wall.