Slidebean offers you a free integrated gallery of images, icons, and gif animations. Go ahead and take advantage, there are tons of them. Of course, you can also upload your own images.
Just Add Content Block to the slide and select whether you want an image, icon or gif. Click on the added block to select an image. A window will pop up for you to browse using keywords.
Within the Design editor of the slide, you can edit the image's Size, Caption, and Cropping style as well as changing the image. Just click on it and a panel with the editing options will show up.
To have a Background image, go to the Design editor and click anywhere on the slide. A panel with options for the background will pop up and you can choose an image there. You may also use Icons and Gifs as backgrounds.
Once added, you can Dim it for better contrast.
Please keep in mind that images in our gallery are mainly sourced from Flickr and a tiny Flickr logo will show in the corner whenever you use them. Remember it's important to give credit to the image author 😉