She probably using the prostetic chest piece, like a lot of cosplayers do now a days..
Its normal for breast size to fluctuate a bit.. but not to several different sizes during a set xD
If you mean the "Access to Full Nude art of my cosplay."
Its drawings, not actual nudes which people seems to think for some reason, unless its changed now(which i doubt)
https://cyberdrop.me/a/sJyOkP0E