Depending on the application pictures will need to be resized so that they appear appropriately. You can do this using a photo editing program such as Photoshop if you are familiar with it. A free alternative is Sumo Paint.
Resizing a picture using Sumo Paint
1. Go to http://www.sumopaint.com/app/#app.
2. Click File in the top toolbar and click New Image. Click OK in the New Image pop-up.
3. Click Image in the top toolbar.
4. Select Canvas Size.
5. Set the width to 230 and the height to 153 for slideshows.
6. Click OK.
7. Click File in the top toolbar.
8. Hover over Import to Layer and select From My Computer.
9. Locate your picture and click Open.
10. Click Edit in the top toolbar.
11. Select Free Transform.
12. Slide your image around and resize it to fit inside the frame.
• Hold down the Shift key while resizing the image to maintain proportions.
13. Click File in the top toolbar.
14. Click Save to My Computer.
15. Name the file and select the JPG format.
16. Click Save.