SlideShare is like the YouTube for PowerPoints and slideshows. You can easily create a gallery of images in PowerPoint or Keynote, upload it to SlideShare, and embed it in Weebly with nice buttons to flip through the images. Don't forget to attribute your images either at the bottom of each slide or at the end of the show.
You will need to create an account with SlideShare in order to use this service. Once you have an account, click the orange "Upload" button to the right of the search box at the top of the page.
SlideShare supports PowerPoint files (.ppt, .pptx, etc.) as well as PDFs and OpenOffice Presentation Document (.opd) files. If you are using Keynote, make sure you export your presentation as a PDF file.(File → Export To → PDF; Image Quality: Best).
Once you've uploaded your slideshow, click "View Presentation" at the bottom of the upload confirmation screen.
Copy the URL from the address bar in your browser. Paste the URL into the WordPress editor where you would like it to appear.