What is a JPEG Image
by 
Lina Thorne • Updated · Posted in Photography
JPEG (Joint Photographic Experts Group) is a raster file format, which utilizes compression to store data. It was developed by a group of photography experts, hence its name. JPG is one of the most common and widely used formats for storing and sharing photos and other kinds of images. This format is all over the place in digital photography, web graphics, social media and print media, and for all image editing and manipulation.
Let’s take a closer look at what JPEG images are and understand why they’re so popular.
Compatibility
JPEG files are highly compatible with various browsers. You can open and process your JPEGs (e.g. crop JPG etc.) in pretty much any app or software.
Small size and excellent quality
JPG files usually have a much smaller size compared to GIF and PNG images. This is due to the fact that this format discards all the colors that the human eye can’t make out. What’s more, JPEG images tend to have a perfect balance between a small file size and excellent image quality. So, you don’t have to worry about your images looking bad. This is especially important when sending digital images over the internet or storing them on devices with limited memory capacity.
Easy sharing
Since JPEG is compatible with a wide range of browsers, apps and software, and its files have a small file size, this format is perfect for sharing images online – posting them on social media, filling your website with them or sending them over an email. This is especially true if you compress your JPEG images and significantly reduce JPEG size; this will make sharing them even easier!
Wide range of colors
JPG should be your choice for photos and other kinds of images with a rich color palette. Why, you may ask? That’s because it can handle fine details as well as a wide spectrum of colors – up to 16 million, to be precise. It supports CMYK, 24-bit RGB, and 8-bit Grayscale color spaces. It also displays color gradients smoothly in most cases.
Lossy compression
Frankly speaking, this can be both an advantage and a disadvantage. JPG supports only lossy compression which means that some information is lost from your images nearly every time you save them. For example, if you take a photo in a RAW format and convert it to JPG, you will get a file that is much smaller in size, but which also has a lot less information. For this reason, it’s preferable to have a RAW image for editing as it will give you much more room for experimentation. Lossy compression can also affect image quality in a negative way. But with the right export settings, you can still get photos of high enough quality.
When You Should Convert Files to JPEG
If you need images with no transparency
JPEG is a great format, but it has a drawback – it doesn’t support transparency. Therefore, it’s great for storing and sharing images that don’t have any transparent layers or elements. For example, photos, scans and drawings.
If you want to publish your files online
The vast majority of images that you see online is in JPEG; due to its high compatibility and relatively small file size. This format is perfect for posting visual content on websites as well as sharing your images on social media. For example, Instagram supports only JPEG and GIF formats; PNGs can be uploaded in some cases, too, but it’s not recommended.
If you need high-resolution photos
JPEG is widely-used by photographers. Surely, nearly all professionals and amateurs will set their digital cameras to shoot in raw – to have files with as much information as possible. However, RAW formats can be opened only with special software. You can’t exactly send RAW images to your clients. A JPG converter might help here. Plus, JPEG images will take up less memory space than RAW files. Thus, the majority of photographers tend to convert their photography works to JPEG.
Do JPEG Images Have Any Cons?
Like any format, JPEG does have a few cons, in addition to its advantages. The main ones are:
- image quality is reduced once processed;
- the changes made are irreversible.
Reduced image quality
The image quality will be lower when using the JPEG format than when working with other resolutions. The difference in quality is noticeable, but only slightly. You will often not notice any difference when comparing images with the naked eye. This format will only not work when image quality is a top priority.
Changes made are irreversible
The original file loses its quality when you edit JPEGs. The changes made are irreversible and cannot be restored. But this problem is easy to resolve - you just need to duplicate the original image. You can always return to the original file if something goes wrong during processing.
Where JPEG Images Are Not Used
However, despite its broad popularity, there are still cases when other formats are more preferable. JPEG is not suitable for files, where there are sharp edges, flat color, and a distinct contrast between pixels. For example, graphics, drawings, or text. Usually, for these kinds of files, lossless formats are required.
Also, JPEG might not be the best format for images that you plan to edit in multiple stages. For example, you import a JPEG photo into Photoshop, do some editing, then export it. Later, you import that image again, do more editing and export it. Then, you repeat this a few times.
There’s something you need to keep in mind. When you export a JPEG image from an editing software, automatic compression will occur – even if you just opened it in the editor and made no changes. This will affect color transition, shades, and pixels themselves. A JPEG image loses some details every time it’s exported.
If you need to maintain the original image data without any loss, consider formats like PNG or GIF.
JPEG is never used when the highest image quality is required, and no losses of the finest details are allowed. For example, medical imaging always comes in other, special file formats.
The JPEG format does not support transparency, so it is not suitable for logos.
When You Need to Compress a JPEG Image
First of all, and most often, you will probably need to compress your JPEGs before uploading them onto your website. Why? Reduced JPEG images look just as good as the originals but have a much smaller size. The smaller your images, the less space they will take up on your server and the faster they will load when a person visits your website.
Nowadays, people prefer visual content to text – they perceive it better. And it’s nearly impossible to imagine a website without images, because you absolutely need visual content if you want your business to succeed. What people don’t like is waiting. If images on your website will take forever to load, people will go elsewhere.
Having visual content of great quality is not enough to make your website successful. Your JPEG images need to load quickly as well.
Another downside of uploading high-resolution images of big size is that your browser will try to compress them automatically; except it won’t do a great job at it. Most likely, your beautiful photos will end up looking blurry and pixelated. This will surely drive away some of your potential customers.
If you want your images to look sharp, clean, and professional, you’ll need to reduce them by using an online JPEG compressor that was designed specifically for it. Only then, you will get great results.
Useful tips on JPEG compression for websites:
- For background images and banners, the maximum file size should not exceed 1 MB.
- For product galleries, portfolios, and other pages, it is better to reduce JPEGs to a size of 500-600 KB.
- For simple graphics, a size of 300 KB will be enough.
You might also need to reduce JPEG size of the files to send them over an email or post them on social media. To avoid wasting any time, it may be better for you to determine which JPEG images you want to compress and batch-process them ahead of time.
When You Need to Resize a JPG image
People tend to resize JPEG images in the following cases:
To meet size requirements
This is probably the most common reason why people resize their images. For instance, most social media platforms have their size requirements for posts, profile pictures and banners. If you want to add a JPEG photo to your digital resume, there’s a high chance that it will need to have certain pixel dimensions.
Online marketplaces tend to have size limitations for photos of products. If you want to add an image to a blog post, its size will also matter. Its width should be the same as the width of the text. At the same time, its height shouldn’t be too big. Your JPEG image shouldn’t take up too much space on the screen.
To reduce the file size
Large-sized JPEG files can take up a lot of memory space and have a negative effect on the loading time. In fact, you should reduce the file size of an image as much as possible if you want to post it on your website. JPEG compression might be a much better strategy to deal with this issue because when you compress images, you reduce their file size drastically. But if you don’t have a website and simply want to free up some memory space, resizing a JPEG image should be more than enough.
To avoid quality loss after automatic resizing
In case you don’t know, when you post images on social media platforms, they get automatically resized and compressed. So, for instance, if you don’t resize a JPEG image before posting it on Instagram, the platform will resize it automatically anyway. But due to this automatic resizing, your image might end up looking blurry and pixelated. To make sure that your image looks the way you want it to, you’ll need to resize it beforehand, using a good image resizer.
To optimize JPEGs for different devices
These days it’s quite common for people to visit websites using their mobile devices – smartphones and tablets. If you have a website, you need to make sure that your visual content looks sharp, clear, professional and appealing not only in the desktop version, but in the mobile one, as well. This can be done by changing the pixel dimensions of your images with the help of JPEG resizer.
In Conclusion
Now you know what a JPEG image is and can use this format exactly where it is really needed. Regardless of where you publish your JPEG photos, try to get the most out of them.