What are you trying to post photos from? If you are trying to use photos from an iPhone the “live” photos are too big. You can screen shot them and they’ll be a small enough file size if you want to use a cheat/work around
I found that, with a I-phone, the system will not take anything except a square picture...not an elongated one. I think the default on the phones is an elongated one, so try changing it to square or at least 4:3 aspect ratio & see what happens.
Here is a simple post I did a couple of months ago about photo size and what to do with each photo. Hello, Taking photos is simple. These days, it is point and shoot. So, what you get in the screen is what is posted, usually. But, some websites have limitations as to how big a photo can be. There is no reason to enlarge the photo to take up the whole screen. When a photo is decreased in size, usually, it is not blurry or fuzzy as most photos become when enlarged. A clear photo is so much better than one that is full page and blurry. Quality overcomes quantity. Here are some examples of your situation and normal computer programs available on all computers. No phones or tablets, larger laptops or home computers have such programs as part of the whole set up. it might be as simple as pasting the photo on a Word Document and taking the corner bubbles and moving them inward to resize the whole photo. that is the simple way... but it does not always work... Pick a photo from your files. On the photo program, once the photo is showing, right click on the mouse and up pops the interim screen to show what is below. A whole list of choices to do with the photo shown. Go to the wording that says Resize Image. Click on that and now, a new pop up screen shows up. All you have to do is change the numbers in the width and height to make the image smaller or wider or such. Or, once you post the image on your Microsoft Word or any word program, you can just cut the image down to get rid of the excess and center in on what is important. Jnaki Most point and shoot cameras and phones have good color. This is where composition comes into play as to what you want to show. So, cut down the size of the photo and get rid of folks standing around a car or get rid of the trees in the background. Most posted photos are from the internet and the original photographer just takes a hot rod sitting in a row of other cars. That is your choice to do it that way… YRMV What photo program does your computer have to work with your photos?
I have that problem with my iPhone for pictures I take. I just use the crop feature and trim the background down a little bit, then I can upload them.
When you go to select the photos you can select the quality on a iPhone check the options and choose the smaller size
Here is a free app I downloaded to my IPhone, it allows you to customize the height and width of the image and download it for free … Jim