My colleague was doing this to get code and files out from his company via email by appending base64 encoded files to a png. However Gmail now rebuilds images

My colleague was doing this to get code and files out from his company via email by appending base64 encoded files to a png. However Gmail now rebuilds images to protect against malicious code and it completely strips the appended files from the image. Edit: he told me it was because his boss had journalling turned on and saw every email sent and received in the company and he thought it was funny to bypass the boss for personal stuff.