Now... What I will say is gleaned from many discussions about 
IP/cr; nor am I a lawyer, but hopefully I will be soon~ 
;)

Back to the original post, saying images on eBay are 
"public domain" is like saying images found on Usenet are 
"public domain" - which is perfectly false, 99% of the time 
(unless the originator truly indicates something is 'public 
domain' and therefore free for the taking). This isn't a 
matter of "opinion." 

People like to claim that taking a 
picture blah blah of something (which is already protected by 
IP/cr law) makes you the owner of said picture; this isn't the 
point, intellectual property is intangible precisely 
because it protects creative ventures regardless of medium. 
If you write a poem and publish it, it is your property 
regardless if it's burned to CD, screencapped, or whatever. 


Cel images can be considered analogous with 
screencaptures of movies - which are also intellectual 
property and outside of fair use (which people abuse too much 
and there's no such thing as 'absolute fair use' with clearcut 
definition) - are illegal to post en masse. This means that the 
average image repository (screencap galleries, cel 
galleries) is illegal, and since it started out as illegal, 
reposting doesn't "clean" an object of illegality.  Even 
giving credit to a party who explicitly stated they did not 
want retransmission of their [object] does not clear anyone 
of liability. People have to realise that IP rights are 
transferrable regardless of location or medium. 

Saying 
not charging money for an IP object is legal because it is "fair 
use" is also generally false; profits from an IP object 
basically just determine how much you pay in damages, it 
doesn't make it more or less illegal to steal.

Also, 
outside the legal issues, reposting someone's cel image is 
typically assertion of ownership (of the cel, not the IP/cr), 
which has been covered in many previous threads - it's just 
plain poor netiquette to do so. Too bad people can't be 
punished for just being rude. ^^;