Those high-resolution photos from your digital camera are worth sharing, but no one appreciates getting 100MB of attachments in their email or wasted pixels on Facebook. Use Lifehacker favourite IrfanView to quickly resize images for sharing.
There are lots of possible ways to resize your photos — the function is built into most image editing packages, and more recent versions of Windows offer basic resizing within Explorer (and Mac users can use iPhoto). For one-off jobs, you can use online image editors, though that's not a wise idea if you need to resize a lot of large images.
We've focused on IrfanView here because it uses considerably less resources than most standalone image editors, consistently gets mentioned by Lifehacker readers as a useful resource, and offers a really straightforward way to resize large numbers of images at once. Plus, of course, it's free. If you don't already have a copy installed, you can download it via the IrfanView site. The instructions below are based on version 4.25, though they don't vary much for earlier releases.
Before you start on resizing, copy all the images you want to resize into their own separate folder — that way, you'll still have the originals for printing and editing.
Launch IrfanView, click on the File menu, and select Batch Conversion/Rename. (Keyboard shortcut junkies can simply hit B.)
Choose the folder where your pictures for resizing are located under the Look in menu (top right).
Click on the 'Add all' button to add them all to your processing list.
Click on the 'Use current ('look in') directory' button in the left-hand column to specify that your resized files will be saved in the same folder.
Select your file type under 'Output format'. For photos, JPG is generally the best option. For online purposes, you don't need to maintain 100% image quality. After selecting JPG, click on 'Options' and specify a Save quality setting of around 70, then click OK.
Tick the 'Use advanced options (for bulk resize)' button.
Click on the 'Advanced' button, which brings up a formidable-looking dialog filled with options — fortunately you can ignore most of them. Firstly, located the 'Overwrite existing files' option under Miscellaneous on the right, and tick it.
Then tick the 'RESIZE' box on the left. Select the 'Set new size' button, and then select 'Set one or both sides to', and choose a suitable width. For email sharing, 640 is a common choice. Make sure two options are ticked below that section: ''Preserve aspect ratio (proportional)' and 'Use Resample function (better quality)'. Click OK when you're done.
While there are many other tweaks available, those basics will do the job. Click on 'Start Batch' and IrfanView will begin resizing your photos, saving them automatically in the same directory with the same name. From there, it's easy to email them, or share via your favourite social networking site.
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