(Though not what is being discussed here [since PJ has confirmed
that it _is_ web pages he means], that's not _entirely_ true: the
JPEG file format [and possibly others] does have provision for
embedded text in at least two places in the file. In Irfanview,
view a JPEG and type I then C to view/edit one of them; other
image manipulation tools are available.)
Right, you're referring to embedded EXIF and IPTC tags, but I don't
think that's what he meant, since I don't think there's any way to
disable those tags independently of the images themselves. If you can
get the picture, and if it has the tags, you'll get the tags.
You don't have to save it - you can just view the source. (In many
browsers, anyway - certainly including Firefox.)
I find that whatever the scripting that tries to prevent you from
saving the picture directly usually obscures the picture's URL, too, so
just viewing the raw source won't usually tell you what you want to
know. But Firefox's View Page Info will almost always find the copy
that's hidden in the browser cache.