Base64 Utility is your one stop shop for all of your base64 encoding and decoding needs.
Base64 Utility is able to open PDF files from external sources, such as Mail.app. Simply choose to Open With... Base64 Utility.
Base64 Utility also handles any copied image. Simply copy the image, then create a new file inside of Base64 Utility.
Need to email whatever youve decoded? No problem. Email directly from the utility.