You can email the pics to yourself then adjust the size before posting. Also, Apples latest release of Monterey allows you to convert their pic's to a lower quality JPG file.

If you are on Mac OS, Preview has an easy to use mechanism for changing images sizes and gives you quite a bit of control. I believe it is the default image viewer on Mac. If you have the photo open select the following from the menu bar
Tools > Adjust size...
You'll get this window. Keep Scale proportionally checked. Depending on the level of detail you need to display, enter something like 600 for a width or height value. The other will value update automatically to maintain proportions. Setting your Resolution to 72 is usually a good choice for screen images.
Click to view attachment

Thanks guys….let me have my resident tech “expert” give suggestions a try.

So we only use I pad….Monterrey only available for I Mac
Still searching for solution

Got an app

What is the preferred size for here?

I have used IRFANVIEW for 20 years. Great for editing, resizing, color correction, and format conversion. Even can autocorrect file type if incorrect. Not much I do not use it for.

MS Paint: Open, resize and/or crop to remove the extra junk that is part of the picture , save or "save as" if you want to keep your original, done.

Will also solve the pictures in wrong orientation.

...I know MAC are more pleasant to work with, but when it comes to using CAD like SolidWorks or NX, there is just no way...

Edit: size? I typically do about 300-400KB

www.compressjpg.com will reduce size. You upload the file, it compresses it for you (usually about 30-40%) and then you download it.
It will compress most file types, even though the name is compressjpg.com