Have you cleared the browser cache? If that doesn't help, the reason must be in the file. Either you are using a wrong file (unfortunately, the filename is not shown in Expert UI), or you made a mistake while editing.
I assume that you have edited an existing file and not renamed it or created a new one.
Raspberry Pi 3 Model B Rev 1.2
Raspbian GNU/Linux 10 (buster, 32bit)
RaZberry by Z-Wave.Me(327) ZW0700 7.21.00 07.42/17367041 1025/257
Z-Way version v4.1.2 from 2023-10-18 03:34:26 +0300
There is nothing wrong with this file. If you now prove that Expert UI pulls in exactly this file, then you have to look somewhere else entirely.
Raspberry Pi 3 Model B Rev 1.2
Raspbian GNU/Linux 10 (buster, 32bit)
RaZberry by Z-Wave.Me(327) ZW0700 7.21.00 07.42/17367041 1025/257
Z-Way version v4.1.2 from 2023-10-18 03:34:26 +0300
I took the description of another device without image, added your image, and after I cleared the browsers cache the image was shown in Expert UI.
Raspberry Pi 3 Model B Rev 1.2
Raspbian GNU/Linux 10 (buster, 32bit)
RaZberry by Z-Wave.Me(327) ZW0700 7.21.00 07.42/17367041 1025/257
Z-Way version v4.1.2 from 2023-10-18 03:34:26 +0300