Resizing an image for your site will help you be able to upload images faster, and page load speed will be faster.
When using image to place in banners we recommend 1280 pixels wide.
Height you can let it scale to size with width so you don't have image distortion.
Adding images to other places, blogs, and modules with text can have a smaller image.
If you do not have a photo editor on your computer, that's not a problem at all!
There is a great online editor tool: https://pixlr.com/
The examples I will be showing is using the Pixlr Express. https://pixlr.com/express/
Select Browse to choose an image that is on your computer
After selecting an image go to 'Adjustment'
After clicking on the Adjustment button, there will be more options that pop up, right now all you need is the resize button.
Resize button will bring up a interface where we can set the size in Pixels.
4000 X 2667 is much to big for website use, and it's file size is 10 MB and we don't need anything that big on the website itself.
For this example, resizing it down to 1280 pixels wide.
If you leave the "Keep Proportions" checked it will automatically change the height to match the new Width of the image.
After successfully resizing the image go ahead and hit the save button at the top of the interface.
Now you can use your resized image on your website!
If you would like to know how to use Pixlr to do more editing to your image before you use it on your website here is a helpful link to Pixlr Support page that will cover more of the tool.