Tried posting my map, but can't find a way to upload/embed photos.
You are 90% of the way there.
You have already got the image on Flickr.
Visit the image in flickr.
At the bottom right of the flickr web-page, there are 4 icons, Edit, Share, Download and Fullscreen.
Click the 'share' option.
Select 'BBCode'.
In the drop-down, select "Medium 640 x whatever"
The necessary code should appear already highlighted in blue in the box above.
Hit Ctrl-C to copy this.
Paste it into your YACF message using Ctrl-V.
This will paste something like this into your post:
[u
rl=https://flic.kr/p/MvHqbg][i
mg]https://farm2.staticflickr.com/1956/29872313867_b9bcdeb5a7_z.jpg[/img][/url][u
rl=https://flic.kr/p/MvHqbg]Capture[/url] by [u
rl=https://www.flickr.com/photos/paddyirish/]alasdair_alexander[/url], on Flickr
I tend to stick a New Line between the image and the description, so I click between the first [/url] tag and second [url…] tag, and hit the 'return' key, to give this:
[u
rl=https://flic.kr/p/MvHqbg][i
mg]https://farm2.staticflickr.com/1956/29872313867_b9bcdeb5a7_z.jpg[/img][/url]
[u
rl=https://flic.kr/p/MvHqbg]Capture[/url] by [u
rl=https://www.flickr.com/photos/paddyirish/]alasdair_alexander[/url], on Flickr
I've done some fancy stuff to prevent the forum software from interpreting the tutorial code above and actually posting the image.
But if I remove the fancy stuff, then this is the result:
Capture by
alasdair_alexander, on Flickr