Hi all,

I thought I'd send a little info about how to resize images from your digital camera before they are uploaded to our webiste, or even sent to others in email.

Most new digital cameras take some pretty impressive pictures. The resolutions of these images usually start at 2-megapixels and go up to 8-megapixel. And, I'm sure the technology will keep making these images better and better quality which means more megapixels and storage space.

When it comes to websites, emails, and sharing photos, there really is no need to share these images at high-resolution. The high-resolution is better when you're printing. Therefore, before you send any photos or share them, you should consider RESIZING the images.

By resizing the images, you will save a lot of disk space and transfer time. Not to mention, the people on the other side looking at your graphics will like you better because they won't have to sit for 10 minutes waiting for your images to download. Ever get a warning message from your email host saying that you've exceeded your space limits? Go check to see how many image attachments you have in your inbox!!

Anyway, when you upload images to a website, the best thing to remember is 1-2 megapixel... A 1-megapixel image is approximately 640x480 pixels. To get the megapixel rating of an image, simply multiple the width by the height.

When uploading to websites, it is safe to go with 1.5-2.0 megapixel images. This is anywhere from 1024x768 to 1280x1024 or a little bigger. But, most websites (such as ours) will automatically resize your images to a smaller size once you've uploaded them. For instance, we allow images up to 1024x768 here.

If you email an image to somebody... just send a 1-megapixel image (640x480). You will be doing them a favor...

Anyway, there are few utilities available to help you resize images so you can upload them to various websites and/or send to your friends in email. Be cautious though... you want to keep copies of your high-resolution images around in case you send them out for printing or whatever. So, when you resize images, make sure you tell the software to make a COPY and never replace.

Here are a few good software packages:

Microsoft's Power Toy - Image Resizer. This utility is great because it fits right into Windows XP. Simply right-click on the image (or images) you want to resize and it will ask you how big or small to make it.

http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx

Picasa. This is a great image management utility for Windows systems. It's a freebie from Google. The utility will allow you to manage all kinds of graphics on your PC and is pretty easy to use. http://www.picasa.com

Graphics Workshop Professional. This utility is a shareware package that can be used on any Windows PC (including older versions). http://www.mindworkshop.com/alchemy/gwspro.html

Most of the above utilities allow you to resize images one at a time or in bulk. If you have any questions or comments about this article, the software, or any additional hints for our members go ahead and reply.

Hope this helps !!

-- MIke

That doesn't explain "256 colours ... [is] all the web displays anyway" though - there are 216 "web-safe" colours but that's not to do with images. Anyway, JPG's are always 24-bit (or 8-bit greyscale). It's how the compression technique works. If you convert to 8-bit then save as JPG it's converting it back to 24-bit. Don't think you'd save any space doing that...

OK you got me curious So I did a small test -

First picture, Parking Lot (many colours).

Saving straight JPG highest quality - 353KB

Convert to 8-bit, save as JPG highest quality - 405KB

Convert to 4-bit, save as JPG highest quality - 374KB

Convert to 1-bit, save as JPG highest quality - 147KB

So as you can see you have to go down to 1-bit before you actually make any space saving for this picture! What about adjusting quality though?

Saving straight JPG 50% quality - 38.6KB

Convert to 8-bit, save as JPG 50% quality - 40.6KB

Second picture, Man at desk (fewer colours).

Saving straight JPG 50% quality - 46.0KB

Convert to 8-bit, save as JPG 50% quality - 46.1KB (nearest colour, error diffusion was larger)

Third picture, Circle (very few colours).

Saving straight JPG 50% quality - 13.2KB

Convert to 8-bit, save as JPG 50% quality - 13.2KB

So this is about the same! Thing is, if you saved this one as a GIF it's only 8.63KB. So from this small test I'd say that converting to 8-bit before saving as JPG is going to increase size, if anything.

Sorry to those who don't care, but I'm sure you'll be interested in these results Gav!

The basic rule of thumb when choosing file format for web display is what does the actual image look like. For everyday photos that are complex in nature, Alfadogs parking lot for example, the best results will always come from using jpeg due to the (incredibly complex and migraine giving) algorithms it uses to compress. For much simpler images like the yellow dot then gif is the way to go, that could probably be taken down to around 16 colors and still maintain an acceptable degree of anti-aliasing on the black/red red/yellow borders. OK, I got it down to 11 colours at 5.257k for all those that don't care

Adobe PhotoShop 'save for web' function is really spot on for allowing you to see in real time how different levels of compression affect or different formats the image. For most of us though saving a photo image at a medium jpeg setting will be perfect!

Cheers,

Rob

Jaded Multimedia Veteran who can still remember having to make web sites using the web safe palette - ugh!!

Carl, there is no automatic 'resize' option from using the context menus (right clicking on image)...you have some 3rd party application that places that option in there.

Although hard for everybody to afford, my 1024 x 768 images are coverted to less than 200kb by photoshop...see my gallery...and no, they aren't 256 color, try changing your color to 256 colors and you'll see what I mean...that's not very many colors!