Is it OK to use Dropbox or Google Drive or similar to put pictures in my For Sale threads?
I already have accounts in these and other Cloud sharing apps.
You can send links to uploaded pictures to anyone and they don't have to have an account to view the pictures.
Bear in mind that the minimum requirement in the rules is a proof picture, and if it's not in the thread then you aren't realy complying
On a general point with a link to browse the photos, it's then up to potential buyers to click away and go off browsing
If you look through some past sale posts and then think about what ones are good for attracting buyers
does the title give you an idea what's for sale?
(Kit bag sale tells you little - unless it's a bag being sold). If you're on the lookout for a Rotor or Spire then you're going to be looking in the sales that mention them
Does fhe thread show you what's for sale?
A line of embedded pictures lets people scroll the post and see what they want, if they are on a phone then it's much more of a nuisance to have to open more links
It will do you more good to put pictures on a hosting site, or attach them to the thread (scaled to a reasonable size)
If you were to post the proof picture plus a photo of each item then you've satisfied that, and if there are more photos of different angles, details etc then use your preferred method and link