How to Resize Your Images Without Losing Quality

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Not every image you take or upload to WordPress is going to be the correct size for your content. And we’ve all had the experience of trying to make an image larger and having it become stretched and distorted. This post will walk you through the basics of enlarging and shrinking your photos without losing quality.

General Information

Why Do Pictures Lose Quality When We Make Them Bigger?

Because most resizing programs just change the width and height of each pixel instead of adding more to compensate.

Example of Pixels

Bitmap photos are the most common format for online pictures (JPGS and PNGs are examples of bitmap formats). Bitmaps are made up of a grid of pixels where each pixel has a single color. If you zoom in on Bitmap images, you can even see small squares. Each square is a pixel!

The most common method for resizing an image is to either make each pixel smaller or larger so that the total width and height match the size you want. Unfortunately, once each pixel gets too large, it is visible to the naked eye and the resulting image looks very pixelated and blocky. This also explains why reducing the size of images doesn’t necessarily make them lower quality. Since each pixel gets smaller when you shrink an image, you don’t even notice.

Fixing the Pixelation Issue

Why not just keep the pixels the same size and add more of them when enlarging? Simple, right?

It is actually pretty hard to extrapolate the color of each pixel and add new ones. The most advanced resizing programs use a technique called Fractal Interpolation or Resampling and can calculate the color of each pixel or the number of pixels based on the resize that needs to be done. Keep reading to find the best options on the market to help you enlarge your photos.

Fractal

Resizing vs. Resampling

Resizing - Keep the number of pixels in the image the same and increase the width and height of each pixel to make the image the correct size.

Resampling - Change the number of pixels in the image and use software algorithms to calculate the color of each newly added pixel.

You can also resample images when reducing the size of them. This process will actually remove extra pixels that don't need to exist since they aren't visible to the naked eye. A normal resize would just reduce the size of each pixel, but if looks fine to begin with, why not go a step further and take out pixels that bloat the size?

Bicubic Sharper vs. Bicubic Smoother

These are common resampling terms in many software programs. Use the sharper option when reducing the size of an image and the smoother option when enlarging a photo.

Best Software for Resizing

Photoshop

Adobe Photoshop is one of the world leaders in photo editing and is great and making images larger, smaller, or take up less space. In Photoshop, it is as easy as checking the Resample Box in the Image Size Dialog Box.


Perfect Resize

This is a standalone program (that also has an Adobe photoshop plugin) made by On1 which builds high-end photo editing software. There are two versions of the software. The standalone product can be purchased for ~$80 and a bundle that also includes the photoshop plugin for around $130.

Depending on how professional you need your photos (and how often you enlarge them) we recommend buying the more expensive options that includes the plugin. It is a lifesaver and will make sure you can enlarge any photos you want for your blog or website. Here is a video demo of using the resize tool to see if it is right for you:


​Gimp

Another option for those of you on a tighter budget is to use a free software program called GIMP (GNU Image Manipulation Program). The algorithms it uses to enlarge photos aren’t as technically advanced as Perfect Resize (since it is open source), but you should definitely check it out to see if it is good enough for your needs. Here is a video on how to resize images using GIMP:

Online Websites

There are also a few websites that have image resize options. I haven’t personally used any of these, but they do use resampling and are probably worth checking out to see if the resulting image quality is good enough for your needs:

http://www.photoenlarger.com/

http://www.imageenlarger.com/

http://resizeimage.net/

Use Other Graphic Formats

If you are creating custom images for yourself you can also look into using SVGs instead of bitmap images. SVGs are a more advanced image format that encode how the image should appear in an XML format. This allows them to scale up and down without losing any quality.

If you are creating new pictures, always check to see if you can get the .svg file. It may be more expensive, but you will have a lot more flexibility and can make it whichever size you want without worry about quality issues.

Final Thoughts


As bloggers, we work with images everyday and understanding how they work and the problems that come with them helps us provide the best experience to our visitors.

We hope this post taught you something new. If so, try it out for your next blog post and see what you think!

Did we miss something? Have more questions? Leave them below in the comments!

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