How to Resize Your Photos for Easier Online Sharing
The world has become snap-happy. According to market research firm InfoTrends, 74.5 billion photos will be shared in 2014 — on social networks, via text messaging or (to a far lesser extent) by email. We will also make 12.8 billion prints this year.
But as we explain in the article "How Many Megapixels Do You Really Need?," there's a major disconnect between what cameras and phones are capable of capturing (typically 8 to 20 megapixels) and what you can share on social networks (0.15 to less than 5 MP). Even some tablets can create large photos (2 to 8 MP). Why does that matter? Because photos with too many megapixels can increase upload times, are sometimes rejected by social sites and email systems, and can clog up computer and device storage.
Although it may seem counterintuitive, an overabundance of megapixels can actually degrade image quality. When a photo file is larger than needed, automatic software (on websites or even in your desktop printer driver) will indiscriminately throw away what it guesses to be extra pixels, even if those data are key to the image.
Depending on what is important to you, there are three choices to bridge the gap between how large a photo your device delivers and how much resolution you need:
1. Set your device to capture smaller image sizes.
2. Resize your pictures using photo software, before you share them.
3. Upload the photos as-is, and let the site resize them.
See the chart at the end of this article for a guide to how many megapixels you need for different social networks or for prints. (As another example, most of the images in this article are no larger than 1 MP, and the chart is 1.4 MP.)
Capture smaller images
It's generally easy to choose lower photo resolution on cameras and in some phone apps. In your camera or app menu, go to the Settings tab or section, and select a lower resolution or smaller image size for the photos it will capture. Not all built-in phone camera apps may have this option: You may have to install a third-party app, such as ProCam 2 for iPhones.
For most social sharing, as opposed to print, 5 MP will give you plenty of data, including enough for some cropping. If you don't foresee considerable cropping or prints, as small as 2 MP will be fine.
Adjusting resolution on a Samsung NX300 mirrorless camera.
Adjusting resolution on a Samsung Galaxy Tab 2 smartphone.
Adjusting resolution on an iPhone in the ProCam 2 app.
- If all you want to do with your photos is share them digitally, this is the easiest and most efficient method.
- A good camera image processor can probably resize its photos better than a Facebook or Twitter algorithm can.
- If you think you may want to print some of your photos, or crop them to use only a very small portion of the capture, you may not end up with enough resolution.
If you think you will want to crop your photos to zoom into on a specific section, you'll want to have captured your picture at a higher resolution. This photo shows my dog Watson far off in a landscape scene. (The original photo was 12.4MP, but the version here has been reduced to 0.54MP.)
Credit: Sally Wiener Grotta/Tom's Guide
I cropped the photo to get a close-up of Watson, and the quality is still sufficient for posting online (as we've done here).
While image quality is not defined by the number of megapixels alone, having too few for the intended display or print will result in the loss of details and possibly a pixelated look.
FYI: Another option that is available on most cameras, but on few phones or tablets, is to change the image quality or compression level instead of the resolution. It's best to avoid this and set your camera to the highest quality level. Compression deletes any detail that the algorithm feels isn't important, and that can significantly reduce image quality. Also, compression is cumulative: Each time you save a JPEG image (which is already compressed) — for example, when you produce a cropped copy — you lose more detail.
Use editing software to resize your images
All photo-editing software has an image size or resize command that's great for downsizing your too-large photos to the appropriate sharing size. (I do not recommend using it to make your pictures larger, such as for a big print. You're asking software to invent image data, which doesn't look good.)
There are a variety of good editing apps. Some, such as Paint.net and Pixlr, are free. But the best ones will bite into your wallet. Adobe Photoshop Elements, for example, runs about $70, and the pro-level Photoshop Lightroom costs about $150.
Image resizing in Paint.netWhen resizing an image, make sure the proportions or aspect ratio are locked. That way, when you change one dimension, the software will automatically calculate the other dimension, to keep the image from being distorted.
- Resizing photos in software gives you full control over what your picture will look like.
- Photo experts usually prefer this method to ensure the highest image quality.
- You can resize a copy and save the original file, in case you want to print or crop more later.
- You'll need the photo software, and the best programs are a bit pricey.
- It takes time and some know-how to edit all your photos before sharing them.
- You won't be able to upload on the spot, as you otherwise can with a smartphone or Wi-Fi-enabled camera (connected to a smartphone or hotspot).
Let the site resize your images
If all you want to do is take and share casual snapshots, you can leave all the resizing up to the sites. When you upload your photos to social networks and photo sharing sites, their system will either automatically downsize your pictures or reject them as too large. (For instance, Twitter will reject pictures larger than 3MB, so you'll have to downsize them first anyway.) True, the automatic resizing can degrade image quality because it's fairly simplistic. However, it can take an experienced eye to see the differences between best and so-so quality, especially when you're viewing low-resolution pictures on sites such as Facebook or Twitter.
- You don't waste time on things that may not matter to you, such as futzing with camera settings or photo-editing software.
- You'll still have the original, higher-resolution photo on your device.
- You can upload on the spot if you have an Internet connection.
- Uploading and sharing large image files is far slower, due to their size.
- Email systems and some social networks reject large files.
- Image quality can be degraded.
Sometimes you can have too much of a good thing — and that's the case with megapixels these days. While the resolution of cameras keeps shooting up, places to display the photos are hardly keeping pace. For detailed guidelines on the resolution you'll need, see the chart below.
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Sally Wiener Grotta is a fine art photographer, author and speaker who has been using and writing about digital imaging from its beginning. You can connect with her @SallyWGrottaand on Google+ and Facebook.