It's not going to be a "virus", it's actually registered by Yahoos.yimg.com
resolves to 188.8.131.52
and a whois lookup says
% This is the RIPE Database query service.
% The objects are in RPSL format.
% The RIPE Database is subject to Terms and Conditions.
% See http://www.ripe.net/db/support/db-terms-conditions.pdf
% Note: this output has been filtered.
% To receive output for a database update, use the "-B" flag.
% Information related to '184.108.40.206 - 220.127.116.11'
% Abuse contact for '18.104.22.168 - 22.214.171.124' is 'email@example.com'
inetnum: 126.96.36.199 - 188.8.131.52
descr: Yahoo! Europe
descr: Abuse reports to firstname.lastname@example.org
status: ASSIGNED PA
role: Yahoo Europe Operations Department
address: Yahoo Europe Operations
address: 125 Shaftesbury Avenue
address: WC2H 8AD
remarks: trouble: email@example.com
source: RIPE # Filtered
% Information related to '184.108.40.206/20AS15635'
% This query was served by the RIPE Database Query Service version 1.88 (WAGYU)
You could try clearing your web browser cache then restarting your browser .. and/or disabling any browser add-ons.
But as I said, it's NOT a "virus", if anything it'd be a simple hijacker .. but most likely just yahoo serving up adverts or something.
If in doubt and paranoid, reset your browser back to defaults by renaming it's config directory in your home folder .. if you want to do this (but be aware you'll loose ALL passwords/bookmarks/etc.) and you're running Firefox...
With Firefox closed
mv -v ~/.mozilla ~/.mozilla-backup
now when you next open firefox it will be back to defaults and completely clean