Most MLSs have a limit for the size of pictures. The most common size limit is 5 MB. There are several ways to change the size of your photos so the MLS will accept them. Here are a few ways:
On your phone or camera:
Cameras or the camera app on your phone allow you to set the size of a photo. Most people have it default to full size images, but this may be larger than you need. You can change the File Size to High or Medium to save them as smaller files.
On a Windows Computer:
You can change the size of any image most easily inside the Paint application.
Open the file in Paint by right clicking on the file and selecting "Open with" then select "Paint".
In the main menu, one of the options is "Resize". Click on the resize button.
Usually selecting 75% does the trick. Type in 75%.
Click the "OK" button.
Save the file.
Please note, landscape-oriented photos are preferred over portrait-oriented photos as some websites may crop portrait style photos.