This easy way to resize your images for digital presentation uses the crop tool with image dimensions 1400 x 1050 for Landscape format applied in the crop toolboxes. The method you follow slightly differs depending on the format of your image.
This method works in both Photoshop and Photoshop Elements. Other image editing packages are likely to work in similar ways.
Please note that the dimensions mentioned in the video are out of date. Please use 1400 x 1050.