From what I know, M-bot does not delete artwork on its own. All M-bot does is send a message to inform the user that their submission was taken down.
Most of Newgrounds is manually moderated, which means that a moderator took a look at a reported submission then deemed it as rule-breaking then took it down. If art violates the art guidelines then it is taken down. Art Guidelines can be found here: https://www.newgrounds.com/wiki/help-information/terms-of-use/art-guidelines
If someone believes that their art actually follows the guidelines and has been wrongly removed, have them try to contact an art mod. They will look into it to confirm whether the submission is actually rule-breaking. List of mods can be found here: https://www.newgrounds.com/wiki/help-information/site-moderation
Mikoma
From what I know, M-bot does not delete artwork on its own. All M-bot does is send a message to inform the user that their submission was taken down.
Most of Newgrounds is manually moderated, which means that a moderator took a look at a reported submission then deemed it as rule-breaking then took it down. If art violates the art guidelines then it is taken down. Art Guidelines can be found here:
https://www.newgrounds.com/wiki/help-information/terms-of-use/art-guidelines
If someone believes that their art actually follows the guidelines and has been wrongly removed, have them try to contact an art mod. They will look into it to confirm whether the submission is actually rule-breaking. List of mods can be found here:
https://www.newgrounds.com/wiki/help-information/site-moderation