I wanted a way to store my photos and videos from iMessage. Currently, iMessage does not offer a native (or automated) way to save files to Photos. Hazel facilitates an automated way to save your files.
Next, I created a Hazel Rule to run on my MacBook. The rule runs on the Attachments folder located here ~/Library/Messages/Attachments. The rule copies the files to a folder that I created under iCloud named From_iMessage.
Here is what my Hazel setup looks like:
The last step is opening Messages on my MacBook. Once it opens, select an message, and click on Details.
Once you click Details, scroll to the bottom of the Photos, and click Download. This process downloads all photos from iCloud to the Attachments folder. As photos download, Hazel Rules will run and copy the files to the folder you created.
Once you have completed this process, you can leave the rules in place, and Hazel will continue to copy photos.
Please feel free to leave comments and questions!