Chrome browser extension - code
Your platform is Windows with the latest Chrome browser and you have a Google Voice phone number. Google Voice supports send/receive text messages with image/photo attachments. Downloading received photos, however, is inconvenient. You can download one image at a time with minimum 5 clicks - open, right-click, Save image as, Save, return arrow(GoBack).
Two additional issues are that

This extension shows all photos of a thread (conversation) in a compact,
easy-to-scroll list. It provides a quick one-click download for all images currently in view, and a list of clickable thumbnails to download individual images. Images are named according to the date they were sent or received.
Downloading photos and images sent to your Google Voice number becomes much easier.
► More Tools ► Extensions (or just copy link chrome://extensions/ into the address bar)
in the extensions menu
Notes