Restrict Attachments to certain types (AttachmentPlugin)

I want to restrict the types of files in the AttachmentPlugin, so that only defined types (for example .png, .jpg and .pdf) can be attached and NOT .doc or .docx.

Where can I do this?


@ErnstZlo This isn’t to do with the Attachment plugin, which only reports on attachments.

phplist doesn’t support restricting the types of files that can be attached to a campaign.

Thank you,
then it seems that I have to do this on my own.