IPhone – Chrome cant show image when using cellular data. but working fine when using wifi

It's stored in an extended attribute on the file. Specifically the com.apple.metadata:kMDItemWhereFroms attribute. It may stay with the file when you move it to different computers, but it depends on the filesystem or file sharing protocol you use. If you move it to another Mac on an HFS+ disk, it will likely keep it, but not necessarily if you transfer over the network, and most likely not with an external disk with a non-HFS+ filesystem.

You can check a file by running xattr -lp com.apple.metadata:kMDItemWhereFroms myfile in the Terminal, or remove it with xattr -d com.apple.metadata:kMDItemWhereFroms my file. ls -l@ flag is also useful; it will list the names of xattrs along with the usual ls information.

If you want to remove it from multiple files, have a look at this question: How to remove xattr com.apple.quarantine from all .webarchive files with that extended attribute?

I've noticed this is now solved on my iPhone. I'm not 100% sure how I did it but the 2 notable things I did very recently were:

1. rename the iPhone from "iphone(3)" to "Sam's iPhone"
2. turned off iCloud on the iPhone then turned in back on

Not sure which one solved it; would be good if any one who has this issue does the same and report back to be able to clarify.