"How to" Guideline series is coordinated by Helen Mongan-Rallis of the Education Department at the University of Minnesota Duluth. If you have any questions, comments, or suggestions to improve these guidelines please me at e-mail hrallis@d.umn.edu.

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Why it is important to resize images for use on the web or in PowerPoint

Guidelines by Helen Mongan-Rallis. Last updated: June 1, 2010

The reason why you should resize images if you plan to load images to the Internet for display on a web page or for inserting into a presentation is that image file size matters.

On the web, the larger the image size the longer it will take the web page to load. For users who have slower connections, this matters a lot. Image size also matters a lot when you insert images into presentations such as PowerPoint, because if you keep the image at its original size, and insert 10-20 images into your presentation, your final PowerPoint size would be huge!

The example below show you why resizing makes such a difference. In this example I cropped the largest photo shown below from a larger image whose original size was 3.3 MB. If I didn't change the image size in a photo editing application before inserting it into a PowerPoint presentation, and I had 10 photos of this size in the presentation, this would make the presentation over 33 MB in size -- which is very large (consider that UMD allows a maximum file size for an email to be 20MB -- so you couldn't email your presentation to anyone, and even if you could, it would take a long time to upload and then download the email if you have a slower Internet connection speed).

Demonstrating the difference editing photo size makes

Photo 1: Large

This photo here has an image width of 744 pixels, 180 pixels/inch (ppi), and image size of 2.47 M. I show the photo and the image size properties below it:

Original Photo of Helen & Peanut Original Image dimensions

Photo 2: Medium size

Here I resized the image shown above (Photo 1) so that it changed to a width of 200 pixels, 180 ppi, with a new image size of 182.9 K (was 2.47 M)

Reszied image 200 pixels, 180 ppiPhoto dimensions for 200 p 180 ppi

Photo 2: Small size

Here I resized Photo 1 by adjusting image resolution to 72 ppi which automatically changed the image width to 80 p, and the image size is now down to 29.3 K (from the original 2.47M).

resized image 80 p 72 ppiImage dimensions 80 p 72 ppi

Learn more

  1. Resizing images: why to resize, what size is best, and applications that you can use for resizing images
  2. Guidelines for using free web-based application, Resizr

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