Two girls in a crowd are dressed up, one as the cartoon character Wall-E.
A few girls cosplay at a local event.
Beeing dressed up and in a crowd does not necessarily mean to cosplay. Being in a crowd does not necessarily mean to be at a local event.
Just because two girls are dressed up as a cartoon character does not mean they are at a local event.
Two girls dressed up does not imply they are doing cosplay at a local event.