Resize your photos for uploading to your website gallery or attaching to an email
When sending images over the internet you need to re-size them. Images taken with modern digital cameras are usually too big to attach to emails or upload to a website photo gallery, so you need to shrink them. Many email servers today only 5Mb files to be sent as attachments. Google’s own Gmail allows 25Mb files. So if you’re attaching 10 x 10Mb files directly from your camera SD card;
- 1. It’s going to take ages
- 2. It’s too big for your server
- 3. Your server might take ages to tell you the file/s is too big
If I’m sending an image to a friend, or preparing an image for use on a website, I’ll rarely upload anything over 1Mb (1,000,000 bytes). Each slide you see on the homepage is about 0.2Mb and those are the biggest files on this site. Your camera assumes you want to print the image, so it includes a lot of extra detail that you just don’t need for the web.
Image Resolution
Printing companies talk about resolution in terms of dots per inch. A 300dpi image means there are 300 dots (pixels) every inch and it’s roughly the resolution you need to print a high quality photo. Newspapers are typically only 200dpi.
Monitors
On the web you only need 72 dots (72dpi). Sure – that’s changing with things like the iPad 3 retina display and larger computer monitors, but if you’re forwarding family pics to a friend or uploading a new pic to FaceBook, they don’t have to be large. On the web we usually talk about how big an image is in terms of pixels. For example, this website is less than 1,000px (pixels) wide. It’s easy to work out that, when building this website, my largest image only needed to be 1000px wide. If I were to print the slideshow images out, they wouldn’t be as wide as an A4 page.
Shrinking a big picture will retain (and sometimes even enhance) image quality. Enlarging an image can do the opposite.
Most websites scroll down, so image height is rarely an issue.
How do I optimise an image for the web?
If I wasn’t already using Photoshop, I’d probably use an on-line service such as Pixlr to manipulate my images. In fact, Pixlr is very much like Photoshop and can do most of the basic stuff that Photoshop does. You could probably do all your website graphics in Pixlr. It allows you to upload an image, manipulate it if you wish and then save it as a smaller version. It also does a whole lot of other things to images. Once you’ve uploaded an image, you can apply a myriad of effects filters before saving.
Let’s have a bash…
Using Pixlr.com to resize images for the web & email
Go to http://pixlr.com/editor/ and upload any large (say 1mb or 2,000px wide) image from your computer. It will appear in its own window within the browser.
Double-click the magnifying glass at the bottom of the tool window (left) to resize the image to 100%.
Image Size from the pulldown menau up top and punch 500px into the width field. The height field will adjust accordingly.
Select Image > Select File > Save from the pulldown. You are given a series of optons for resolution, but the deafult is fine.
Give the image a name and save it to your computer. Hey presto. You have optimised an image for use on the web.You can also send optimised images from Pixlr to Facebook and Flickr.
In General, Shrink!
Just remember that, as a general rule, any image that is wider than 1,200px is probably too wide for most websites (unless it’s a background image) and too big to send attached to an email. The images coming out of your camera are much higher resolution. You need to shrink them.
