It’s so important you resize large images prior to uploading them to your blog. I could give you the mile long list of reasons, but just trust me. Nothing above 1000px wide is usually ever necessary, and will kill your load time.
(if you do not have photoshop, you can download a free trial at adobe.com)
How to Resize Images for Your Website
First, you’ll want to download and open this action:
(If you download all of their free plugins, you’ll want to open the one titled “High Definition”)
Once opened, it will take you directly to Photoshop.
Open the photo you would like resized, and then click on the action in your actions panel.
Boom, image resized in the blink of an eye.
Click File > Save for Web. Choose your file type and quality level.
Worth noting: A JPG is going to load quicker than a PNG. I recommend playing with the JPG quality level on your images and using the lowest possible number. 6 is the most commonly recommended, but some images will not look so hot at that level, so just adjust that accordingly.