...
I imagine there is some better way of handling the problem than with
perl, and almost certainly better perl code exists than that below,
but in any case, the following converts back-slashes within 'img src='
paths occurring singly on single lines; eg, it converts 3rd line to:
<img src="public_html/images/Buster.jpg" height="250" width="128"
and leaves other lines as is.
perl -pe 'm/(img src="[^"]*)/; $path=$1; $path =~ s|\\|/|g; s/(img src="[^"]*)/$path/'
It isn't clear to me what your multi-line case would look like, etc.
Note, if some lines have more than one 'img src=' paths on them, run
the script more than once.
--
jiw