I resize all my pictures for sites that require a maximun size or smaller, is my paint app that is available if I right click on the picture in my computer, then click on "edit". I selected re-size, then usually, if it's 3 meg or over, set it at 30% or 40% and click the X. That brings up a screen "save as", which I do and that converts the picture to between 600 and 700 kg.
Then you have to transfer your picture to an online upload site, or send it to a different forum with a "straight from your computer upload system" so it gets "published" to the internet. Then THAT address can be uploaded to this forum within the brackets [IMG] and [/IMH].
Most guys here is an upload site.