Still Images: file sizes

Digital Still Camera

Digital Still Camera

Image copyright LT Scotland

It is important to know the more common file formats that are used to save images and the actual dimension and file sizes because these factors impact in the many different ways you use your computer.

As cameras offer more megapixels and camcorders cope with longer periods of filming consideration must be given to the growing file size needed to store these images and video.

If you take an image from an SD card directly into a document then it will certainly be too large to fit the document’s width. Straight away you have to resize or crop the image using the word processor’s tools. If you just wish to print the document to a local printer then this might not be critical but if you have to save the document to your school server space or send it to a remote printer on the network then the larger the file size the fewer files can be stored in your storage space and the longer it will take to print. In addition, transferring files from your pc to the server and to the network printer will ‘tie up bandwidth’ so much so that as the number of users doing similar transfers grows then storage capacity and network speed falls away.

There is a simple solution. If you just need to resize an image quickly without the need for such improvements then use a simple image resizing tool as explained in the Resizing Still Images page.

Normally, a digital still image will be saved in your camera at a width of just under 3000 pixels whereas the width of a word processed document or older web page is 800 pixels so straight away we see that the image will be far too large.

For a word processed document, resize to either 800 pixels wide (for full page width) or 600 pixels to leave some ‘white space’ around the image (this is a feature employed by graphic design artists).

On a web page the 800 pixel width dates from older pcs but although modern pcs have a standard 1280 pixel width this is still less than half the width of an image taken directly from a digital camera. A web page is also likely to have a navigation bar further reducing the width available for content. Therefore, image width on a web page tends to be at most 600 pixels but more often is much less as the image is used to represent or explain the written content rather than be the sole source of information on the screen. The images in this site are nearly all 300 - 350 pixels wide.

Please download the expanded version of this information to receive a fuller coverage of this important feature of digital imaging.