How to Double the Size of a Photo Without Losing Quality

It’s a classic problem: you have an image, you want to make it bigger, the usual tool does a lousy job, and the result looks terrible. Some editors include filters that help mask or smooth over the quality loss, but there are also advanced programs that deliver far better results. One of the most popular is waifu2x, which we covered a couple of years ago, and which now has an offline edition. If you really want to double the size of a photo, you should definitely give it a try.

One of the most hyped features on consoles, TVs, and Blu-ray players is upscaling. You take a lower-resolution signal, bring it up to 1080p or 4K, and depending on several factors (including how accurate the interpolation algorithm is), the final image fills the entire screen without turning into a quality disaster.

Something similar happens when you enlarge a photo. You open your favorite editor, drop in the image, set it to 200 percent, choose a filter (bicubic, Fant, etc.), and what you get is a bigger image with extreme smoothing or pixelation. Sometimes that’s enough. But if you genuinely want to double the size of a photo without losing quality, you might want to look into an alternative like waifu2x-caffe.

Using waifu2x-caffe to double photo size without quality loss

The entire waifu2x-caffe profile on GitHub is in Japanese, but the only thing we need to do there is visit the Releases section and download the latest Windows-compatible binary (about 200 MB). When you open waifu2x-caffe, you’ll see a field to enter the path of the images or folders to process, plus several advanced parameters. The out-of-the-box conversion mode does magnification and noise reduction at the same time, but you can change that if you prefer.

There are four levels of noise reduction, secondary magnification values in addition to a fixed rate (by height, width, or both), seven models for photos, illustrations, and anime images (waifu2x is especially strong with that kind of content), and a speed section.

Waifu2x-caffe is compatible with Nvidia’s cuDNN module, which speeds up neural networks using the company’s GPUs. The catch is that waifu2x-caffe tries to use it from the get-go, and to download it you need to create an Nvidia developer account. The workaround is to go into the program’s settings and switch from GPU to CPU.

Even without changing much in the settings, I have to admit that waifu2x-caffe performs excellently. My system is far from powerful, and the processor took about two minutes to convert a 1080p image to 4K, but it was worth every second. As always, everything depends on the type of image and the parameters you choose. A bit of trial and error is recommended here, unless you know Japanese and can read the documentation.

Editor’s note: The program supports Spanish, but it has a bug. Edit the LangList.txt file inside the lang folder, change the entry from french.json to spanish.json, and choose “French” from the interface to activate Spanish. It’s a crude and inelegant hack, but it works.

Official site and download: Click here