Image sizing

Have you been in a situation where you need to submit images of a certain size and have felt slightly confused about what you’re being asked and why?  Read on to find out more…

Why are you asked for a particular image size?

You might be asked for a specific image size so that the quality is high enough to be displayed either for print or on the web – pixelated (poor quality) images do not represent your skills favourably.  Equally you might be asked that your image does not exceed a certain size when sending through email or using a form as some mailboxes have a restriction.  Images can take up a lot space – a particular issue for art/design based organisations.

Kilobytes, Megabytes and Gigabytes…
figure 1

figure 1

Kilobytes (KB), Megabytes (MB) and Gigabytes (GB) refer to the amount of disk drive space used up by a file.  There are 1000 KB in 1MB and 1000 MB make up 1 GB.  To find out how much disk space your image takes up, hover over the image in the folder with you mouse until a pop up box appears (see figure 1).  Note the dimensions are also given in pixels.

Dpi (Ppi)

Dpi refers to the amount of ‘dots per inch’ which defines how many dots are printed per linear inch.  The higher the amount of dpi your image is, the higher quality it will be.  This also means that the file size will be larger.  Ppi refers to the amount of pixels per linear inch which is more relevant to digital images intended for the web.  These values are equal- 300 dpi = 300 ppi.

figure 2

figure 2

By right clicking with your mouse on your image (or control and mouse click on a Mac) you can select ‘properties’, which brings up a dialogue box with information about your file.  If you select the ‘details’ tab in this dialogue box, you can scroll down to view the horizontal and vertical dpi (figure 2).

Resizing your images

If you need to resize your image, you will need to do so using some image editing software.  You can use Adobe Photoshop to do this, but if you don’t have this software available there is likely to be some free software already installed on your pc or laptop or free software you can download.  Beware, programmes such as windows ‘Paint’ will allow you to resize your picture either by percentage or by pixels but does not allow you to adjust the dpi, so you may need to find something else.

Free image editing software

There are lots of different types of image editing software you can download such as ‘Gimp‘ and ‘‘ which you can download for free.  The best way to choose software is by looking at reviews like these ones on Digital trends & Tech radar and giving something a try.  If you need help using the software, you can normally find a YouTube video to show you how.