@Mackenzie-Melendy I use "Export As" in Photoshop instead of pre-adjusting the size of my image using "Image Size". Using "Export As" you can tell PS to save your image as a JPG which will automatically be at 72ppi.
You can also save your image by adjusting the percentage level of quality in the image instead of changing the size.
You can tell PS how you want the image resampled when it is reduced (there are I think three different options when you're reducing that each impact the clarity of an image).
Lastly, you can just simply save it at a percentage of your original size or in different formats like PNGs.
For all these adjustments, PS will tell you how big the file is going to be before you save it. That way you can make specific adjustments.
You can find "Export As" in the dropdown menu under "File"> "Export" > "Export As". There is also a Legacy interface that lets you save things "for the web", which does the same thing but uses an interface that's from older versions of Photoshop.
I sometimes bump up the size of the image so that it's bigger and closer to 2500kb (2.5mb) if my image has room by increasing the image size.
Untitled_Artwork.jpg
Untitled_Artwork 2.jpg
Also keep in mind that all the images posted on the forums are clickable, and you can see the image at the actual size you've uploaded it. I think all posts on the forums have set size parameters to which they'll shrink an image to appear in a thread, but clicking on the image itself within each post enables readers to see a bigger, sometimes crisper, version of the images posted.