Compressing images and photos on the computer means reducing the space occupied in terms of Kbyte or MByte, without however resizing the actual image. Whether you want to publish images on your website, or to optimize the backgrounds, or to send photos via email or publish them in some social networks such as Facebook, it can be useful to compress the space they occupy in the face of a minimal loss of quality. This gives the advantage of downloading and uploading them faster on the internet and of being able to send multiple photos via E-mail together. In this guide we will show you how to compress JPG, PNG and GIF images, using free programs and websites that allow you to compress images online without having to download anything.
How to compress images
The key factor when using one of the programs or websites in the guide is that, during the compression procedure, we must not lose too much quality in the colors and in the definition of the outlines, to avoid finding ourselves with an ugly and grainy image.Programs to compress images
The best program to compress images on your computer is IrfanView, the photo and image viewer, equipped with useful multipurpose plugins .
Thanks to the RIOT (Radical Image Optimization Tool) plugin, which can be installed together with the other plugins for IrfanView, by opening an image on Irfanview, we can compress it by pressing at the top left on File -> Batch Conversion / Rename, placing the check mark on Use advanced Options by pressing the Advanced button and finally activating the RESIZE field and Set image size to Megapixel .
By doing this we can compress any type of image by immediately deciding the maximum size of each, thus obtaining compressed files without excessive loss of quality (for convenience we advise you never to drop below 3-4 Megapixels, especially with photos taken with modern smartphone cameras or with SLR photos.
As a first alternative to IrfanView we can download the separate RIOT program, both as an installer and as a portable program.
This program aims to optimize images with the help of some sampling filters. JPG, PNG and GIF files can be compressed and for each type of image there are different options and parameters. For example, for NPCs it is possible to decide whether to maintain transparency or not. When working on a file we can see the preview of the final file in case of compression: in this way it becomes easy to find a good compromise between image quality and file size, simply by moving the Quality line. Using the Batch function it is possible to compress, rotate or resize multiple photos together.
Another program to compress the size of images without losing quality and without making them shell is Caesium.
You can reduce the file size by up to 90% and you can compress multiple images together in one process. The interface is very simple to use and the program is offered with an open source license, so we can use it without problems even in the professional field without having to pay a user license.
There are other programs to reduce the size of the images, useful both for those who have to optimize the images of their website and for those who have to send them via email. The list of alternative programs is available below:
- Very easy to use Shrink Pic with 4 compression levels.
- Image Resizer is a bigger program that compresses, resizes, converts images and also supports RAW format.
- SuperGif to compress GIF images.
- PNG Gauntlet which instead serves to optimize the PNG images used in the layouts of websites.
- Image Optim is a program that we can use on Macs or MacBooks.
- PNGGoo, fast and effective at compressing PNG files, better than PNGGauntlet.
- FileMinimizer, free and very effective at compressing JPG and PNG files without loss of quality.
- NXPowerlite, which works with all kinds of files, to reduce their size in terms of MB so that they take up less disk space.
Websites for compressing images
Squoosh is the best web application to compress images without downloading programs and directly online on the internet.
This free and ad-free website allows you to upload any type of image or photo, including those with a modern format such as MozJPEG and WebP, and to adjust compression so as to decrease the file size without losing quality. The beauty of Squoosh is that it works in real time: the changes, in fact, appear on the screen directly while you adjust the options. There are two preview panes so you can compare the original image with the other compressed variants. By default, the left pane shows the original image. In each pane there is a dialog box that will show you the actual size of the previewed image, to easily compare the dimensions between the two versions. The tool can also calculate the net percentage difference in size of both images for a better sense of comparison. Three adjustment options include resizing the image, to make it smaller while maintaining the aspect ratio.
It can also reduce the number of colors, adjust the noise and the quality of the photo itself. Thanks to the preview you can reduce the quality until you really see a difference with the original image.
A good alternative to Squoosh is definitely Compressor.io.
The site allows you to upload images simply by dragging them into the interface; among its features we find Lossy compression (which leads to better compression but with a visible loss of quality) and Lossness (less compression but intact quality).
Compressor.io currently supports compression of GIF or SVG files, as well as JPEG or PNG.
The file size limit is 10 MB, but only one image can be uploaded at a time.
Another very good site for compressing images of any format is ILoveIMG.
By uploading the images to the site from the PC memory or from one of the supported cloud services (Dropbox or Google Drive), we will be able to effectively compress every type of image, choosing the right compromise between final quality and file compression. Compressed files can either be downloaded to your computer or immediately shared on social networks or in chat, without having to download them.
Then there are other sites with web applications to compress images directly online without downloading programs and they are:
- CompressNow to shrink an image, also good for working multiple files together.
- TinyPNG uses intelligent compression to make PNG files smaller, with no visible loss of quality.
- Kraken allows you to choose how much to compress the image files and to upload them from Dropbox or Google Drive.
- Toolur is another easy-to-use site with an online photo compression tool that can reduce file size almost instantly.
- CompressJPEG.com allows you to compress JPG up to 20 files at a time.
- Image Converter supports all types and formats of images.
- Image Optimizer for compressing JPG, PNG and GIF files only.
Conclusions
Compressing images without losing too much quality may seem an impossible task, but thanks to the free programs and websites that we have reported to you, we can effectively compress any type of image, even the one in the least common format or difficult to compress by its nature ( GIF files for example).If we want to compress the images on our Android smartphone, we recommend you read our guide Compress photos on Android and reduce the size of the images in the phone .
In another article we also talked about programs to resize photos even on sets of images .
