Hi Glassbee, welcome to the Board.
What problem are you having? If it is about how to add an image to your posts, then simply use the "Attach" function below the posting area.
If the problem is about loading an image with a Kb size that is permitted (under 125 Kb) then, as suggested, you need to resize (or optimize) the image.
There is a free utility on the web, that I recommend, as it does a very good job:
www.picresize.com - usually, with that routine, just setting the longest side of an image to 700 pixels will produce a good result.