I read quite a lot of other blogs and forums and one of the things that I often notice is that photographs are often posted that are far larger than they really need to be. Although this in itself isn’t a huge problem, it does mean that when you try to view such an image it can take quite a while to display on your screen, especially if you have a fairly slow internet connection. With this in mind I thought I would write a quick, and hopefully simple explanation of what is going on here and how you can make your photographs much more web-friendly.

Let’s start with your camera. A typical modern compact digital camera will be somewhere between 6 and 12 megapixels, in other words around 6-12 million pixels. In simple terms, the pixels are basically the colour “dots” that make up the image and are contained inside a digital sensor that records the image – the 21st century equivalent of a piece of film. So, if we take an example of a camera that has a sensor that is 4000 pixels wide and 3000 pixels high…………we have a total of 12 million pixels in the sensor (4000 x 3000 = 12 million, i.e 12 mega pixels).

Now, a typical 12megapixel image will actually have a file size on the computer of around 5 – 7 MB (megabytes). A megabyte is just over a million bytes (it isn’t necessary to understand what a “byte” is, by the way, just think about it as a “block” of data), so again, a 6MB image is just over 6 million bytes.

Now, here’s the problem……………………………5-7MB is far too big to send on the internet if it is just going to be displayed on a computer screen. If you have a really fast internet connection, say one that gives a transfer speed of 1MB per second, then it will take 6 seconds to download a 6MB image…….pretty straightforward. But what if you don’t have a fast internet connection?. I use Iberbanda which struggles to get above 100kilobytes/sec (100 thousand bytes per second), in other words around a tenth the speed of a good fast broadband connection. So, instead of taking 6 seconds, that same 6MB example image will now take 1 minute to download from the web server to your screen. Nobody is going to wait that long to view a photo!.

But here’s the thing…………………it’s a complete overkill to send such a large image anyway. A typical computer screen is setup to run at a resolution of between 1000 and 1200 pixels wide. Not too long ago most computer screens were running at just 800 pixels wide. So, it’s completely pointless sending that 4000 pixel wide image from your camera without reducing its size, as it is only needs to fit in a space that is around 1200 pixels wide. By reducing the size of the photo so that its longest dimension is actually less than the corresponding dimension of your screen, you will still have a perfectly decent quality image but its file size (and therefore download speed) will be greatly reduced.

Here’s an example:

Let’s take that 12mega pixel image (remember 4000 pixels wide by 3000 pixels high). If we can reduce it so that instead of being 4000 pixels wide it is only, say, 800 pixels wide by 600 pixels high, we now have an image with 480,000 pixels in total (800 x 600). This will still fill a good proportion of your compter screen, but now the file size is only 1/25 of the size of the original full size image (ie. 480,000 is 1/25 of 12 million). So, our file size has also been reduced (to 1/25 of its original size) to around 200KB (200 thousand bytes). On my lousy Iberbanda connection that image will now only take 2 seconds to download onto my screen, compared to 1 minute for the full-size version!.

The big question is………….how do we reduce the size?. There are various programs  that can be used to edit images and reduce the dimensions – some are free and some aren’t!.

If you intend to spend quite a bit of time editing and organising your images I would recommend one of the commecial editing programs like Adobe Photoshop Elements or Paint Shop Pro. Both of these can be bought for between €60 and €80 and are very powerful tools . There is also a free program called GIMP, which despite its weird name (it stands for Graphics Image Manipulation program…………..obviously!), is actually a very good image editor, though it lacks the organisational features of the other two. Finally, there is another free sofware solution. Picasa is Google’s image editor and organiser and has basic editing capabilities.

However, I am going to show you a very simple way to reduce image size by using one of the standard features of Windows – the PAINT program. This is a very old relic from the early days of Windows and is so outdated that most people now don’t ever use it. But……..it will (just) do the job!. Here’s how:

Using the Windows START button, go to PROGRAMS and then ACCESSORIES, and you will then see PAINT. Open the image you want to resize (FILE/OPEN). I am going to show an example of a full-size image of mine that is 4288 pixels wide by 2848 pixels high:

As you can see by the evidence of the scrolling bars on the bottom and right of the screen, we can only see the top-left of the image because there are far more pixels than can fit on the screen (note: my screen runs at 1920 pixels in width – most people running at 1000 – 1200 would see even less than this of the image).  Next thing to do is go to the IMAGE menu option and select RESIZE/SKEW. This is what you will see:

You will be presented with a dialog box that allows you to adjust the horizontal and vertical percentages. Initially it will show 100%. In the above image I have reduced both dimensions to 20% (you need to adjust both by the same amount or you will distort the image), and then clicked OK.

We now have a resized image. If you want to see the exact size, go again to the IMAGE menu and this time select ATTRIBUTES.

We can see now that the actual current dimensions of the resized image are 858 pixels wide by 570 pixels high. Perfect for screen display!. Just go to FILE/SAVE AS in order to save the resized image. This particular example has reduced the image from 7.9MB to 117KB! (ie 1/67 of the original size), however at 858 pixels wide it will be a perfect size to fit into a typical 1000  – 1200 pixel wide screen.

I hope this has been of some help!