This probably sounds a bit Archaic, but it works, I was having trouble posting pics, with the file to large, thing, so a simple thing to do is, stand further back than you normally would to take the pic, then resize on your phone, then post, hey presto, it works.
Here's some pics of the air line. The pipe with the fitting for the tyre valve I had under the bench, but no doubt you can get the fitting off eBay
The blow gun I got from Screwfix for just under a fiver.
Open the image , right click and select 're size' option . I guess this depends on what kind of OS you use. Just about every photo I take with my iPhone has a file too big for this forum, I could probably change it , but can't be ar$ed . On my digital camera I can easily select a lower grade of image
No use if you post from a phone, but I use the Windows 'Snipping Tool' (set to 'rectangular snip') 99% of the time. You can grab anything displayed on your screen this way, and the size is the same as you are viewing when you take the snip. It also allows you to crop the image at the same time - you just select what you want.
Display the picture on your computer and fire up the Snipping Tool. Press the 'New' button and draw a rectangle around the part of the image you want (or the whole thing):
This is loaded into the Snipping Tool - you then have highlighter and drawing pen tools available if you want to circle something etc.
The content of the Snipping Tool is automatically 'copied' ... so you can just 'paste' in your post and the image is inserted:
You can then re-size it if necessary by dragging the corners.
If it's a large or highly detailed snip you may get a 'too large' error when you go to paste it into your post. If so use 'File, Save As' in the Snipping Tool to save it to a new temporary file on your computer, then use the 'Attach files' option at the bottom on your post and select 'Insert...' , 'Full Image'. You can then re-size the inserted image by dragging the corners again.