Your grumpy Mod from Germany speaking here …
Frequently posters fail to add pics in their posts, so, a few remarks from the janitor:
pic/file size is restricted - for various reasons.
Unfortunately, well known screen-grab shortcut cmd-shift-3 creates full-screen png - nice & detailed, but huge. Too huge.
=> before uploading, use Preview.app to resize&reformat, suggestion: max 1200pix wide (or long) and as jpg.
Cmd-shift-4 allows to drag open a selection rectangle… less is more!
To attach a pic, use the Attach button in the Post Editor.
To insert a pic in your text, you have to Attach it first, then hit Insert
• Does it need a pic? This pic?
Sometimes, a pic tells more than a 1k words, sometimes it lefts the watcher clueless. Mentioned Preview.app has an impressive toolset of circles, arrows, a loupe, colors etc to direct attention. I’m talking to movie-makers, hey, you should know!
• Does it illustrate the problem/post?
A full-size screen-grab of your About-this-Mac doesn’t add any info you couldn’t write in half a line of text. When you discuss a before/after prob, it should be two pics, shouldn' it? Trouble with Inspector settings should show … you got the idea.
• No full-quotes! Please. Just for me.
… ok, there’s no board-rule telling this, just personal preference, sort of politeness … esp. a mile-long full-quote with dozen of pics and an added “yeah, right on” or like makes me arghgh.-
• Ext. Storage
Some prefer to attach a link to some external service … be kind to us, use services which don’t make my Mac going rogue popping up all sorts of ads and ‘polls’ ask membership or whatever.
• Links to pics
Check your link. Which leads to: …
• Check your post after posting it
When I don’t see a pic in your post, you don’t do either. Edit it. No ‘fire and forget’, please.
… this post is beyond 140characters and includes no pics - hmmm? Not so smart.
I'd like to tell what I do when posting screen shots. Open in Preview, 1st thing, Tools > Resize, set width to 1200 (height is going to be whatever). Then Export to a JPEG, 80% quality. That pretty much always works here.
Bear in mind the Mac, and depending on the monitor it is using, can do screen shots at 144dpi, and at a full screen size (in pixels) that makes for a very needlessly HUGE image.
Yeah, your Mac is powerful, but the internet is not that powerful...