Reducing Image Sizes

Introduction

This document is intended to help people new to digital imaging and explain the relationship between image resolution and file size. There are many benefits to using smaller images on your webpage.

First off, web space is a finite resource and should be conserved as much as possible. There is a set amount of space allocated to your website and going over that limit can cause certain elements of your page to stop working.

Secondly, large images take time. Time to upload and more importantly, time for your guests to download. This can be noticed especially when creating complex pages with many large images.

Last, large images are wasteful. Meaning, unless your intended audience has a 21 inch monitor set to a super-high resolution, no one is going to see the true image size anyways. This is especially true for the built-in Image Gallery offered by Trudeau Consulting.

Basically, unless you intend to sell hi-res photos on your website (intended to be printed on a large format sheet), it's best to shrink the picture size before uploading.

---

Resolution

Let's use one of my favorite pictures as an example of how resolution works.
We took this photo during a recent cruise through the Baltic Sea which included a stop at St. Petersburg:

This image as you see it above is 500 pixels wide, and 332 pixels high.
It is about the perfect size for most web users and it is approximately 40kB.

But that's not the dimensions were when we first took the shot. The original image was 3000 pixels wide and 2000 pixels high, and weighed in at a hefty 2.6 MB.

Here's a clip of what the original size was, chopping off a 500x332 pixel chunk:

While this may be great clarity for a photographer, it is really pointless to have that sharp of a file on a webpage (for the reasons stated at the top of this document). Unless you plan on making hi-res shots available to the general public for offline viewing/printing, you should reduce the photo.

---

Step-by-Step

There are a few common tools available to MS Windows owners to reduce the file size of their images. The most common is MS Paint.

1. Open MS Paint and File --> Open the picture file

2. First, check and see what your image resolution is. Go to Image --> Attributes, as seen below:

We can see that this image is 3008x2000 pixels. Ideally we want something that is 700-800 pixels wide.

3. Go to Image --> Stretch/Skew, as seen below:

4. Enter a % reduction in the horizontal and vertical boxes, as seen below. Anything from a 25%-50% reduction should be suitable.

5. File --> Save As. You may or may not want to save the image with a different filename. If you overwrite your original file, you will never be able to get that resolution back, so be careful when choosing a filename.

Also, be sure your "Save As Type" is .jpeg! Saving your file as a bitmap will undo all your hard work, because they are what's known as "uncompresed" files, and are always much much larger than .jpeg's.