DNN Support Center

Image Optimization

This is why we "resize" our images.

If you have ever sent or received photos via email, or attached them somewhere on the web, you know that image size can be a problem. Some websites only allow small images so they load faster and consume less memory, and getting an email with a huge image can be very annoying.  

This is why we "resize" our images.  The aim of optimization is to reduce the time it takes to access a website (or run a program).

The time it takes for a webpage to display is affected by a number of factors:

  • number (and filesize) of images used on the webpage
  • structure of the underlying XHTML code, for example; setting height and width attributes enables the browser to reserve the correct amount of space for an image (before it has downloaded) avoiding the browser redrawing the webpage
  • browser’s rendering engine (how the program is used to access the web loads on each webpage)
  • browser caching: if the webpage, images, stylesheets, etc. are stored locally they do not need to be downloaded
  • user’s connection speed (i.e. dial-up modem will take longer to download a webpage than a cable modem)
  • speed of the server hosting the website
  • Internet traffic

Windows Image Resizer:   Image Resizer

  • Image Resizer will install as part of Windows
  • Right-click on picture
  • Select "Resize Picture" (640 X 480, or smaller)
  • Automatically resizes picture and ready to use
Mac:  Resizing Images Uses Preview

*Preview does not require downloading any software on the Mac

  • Open the image in Preview
  • Select Tools
  • Select Adjust Size
  • Image Dimension window will show
  • Select Fit Into 640 X 480 pixels
  • Select Ok (image has resized once OK is selected)

Another option for a Mac is the free software JPEGmini App from the Mac App Store

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Updated on Fri, 09 Oct 2020 by DNN Con

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