When you are posting look in the tab above the window you are typing in for a paperclip and click it. It should open a pop-up window for you to use. You'll have to browse and open files from your computer and then upload them. Often you will get a message that the file is too large in which case you'll have to resize your pictures down and try again.
I usually use the program "Paint" to resize pictures as it's not hard to use and is standard on every computer I've ever had. Be sure to save a copy of your picture and use it for resizing so that you don't loose your original full size picture.
Following instructions from a fellow member, I email to myself pictures from my phone and then download to the computer and put in a file created by me for pictures. If I use another camera I use cord provided to download on computer and put in file. After you type your comments scroll all the way down and you will see a box that says manage attachments. open that and click on choose file and select a picture than repeat. Works great for me.
The only way I can post them from my phone is to take a screenshot of the pic and then upload it like that.. You can also email the pic to yourself then upload from there.. I never could
Figure out the resize thing from my phone
I try to post pictures from my iPhone 7 plus. When I type on the icon for a picture it tells me to put in a URL... where do I get an URL from a pic I've taken on my phone?
Other Androids should be similar. For this post, I chose my photos from the screenshot folder, since that's what I used. Normally, you would choose your Photos folder.
I can't help with iPhones since I don't own one.