Throughout the backend, you will see guidance on ideal image sizes.
Here is an example:
Below I will share all of the most common dimensions for reference. If you upload an image that is too big in file size, WordPress will automatically downsize it for you. This can sometimes cause issues or slow down the backend, so I suggest always resizing your large images before uploading them to you website.
The same goes for cropping — WordPress has a built in crop tool, but personally I find it easiest to crop my images before uploading. If you do not have Photoshop I suggest signing up for a free Adobe Express account where you can crop and resize images in a breeze.
2880 x 1100 px. Keep in mind that the teal triangle device will cut off the left side of the image. Try to source images where there are no faces or important information on that left side.
750 x 1148px
2200 x 1200 px
1700 x 1140 px