Fichiers BMP et JPEG

Nés au début des années 1990, les formats BMP et JPEG sont deux des plus anciens formats de fichier d’image utilisés aujourd'hui. Les fichiers BMP, qui contiennent des images volumineuses, brutes et de grande qualité, conviennent tout particulièrement au travail de retouche. Pour leur part, les fichiers JPEG, automatiquement compressés, sont généralement plus petits et de moins bonne qualité. Découvrez leurs caractéristiques, leur historique et leurs applications courantes.

image d’en-tête BMP vs JPEG

What you’ll learn.

 
  • What is a BMP file?
     
  • What is a JPEG file?
     
  • What is the difference between BMP and JPEG files?
     
  • BMP vs. JPEG files: frequently asked questions

 

 

What is a BMP file?

BMP stands for bitmap, a raster-based file type designed in the early days of computer graphics to display images independently from devices. Because BMP files are information-rich, they tend to have large file sizes. 

 

Learn more about BMP files

 

 

What is a JPEG file?

The Joint Photographic Experts Group developed the JPEG, now a widely popular raster-based image file. Built around an innovative lossy compression method, JPEGs strike a balance between reducing file sizes and preserving image quality. 

 

Learn more about JPEG files

 

 

What is the difference between BMP and JPEG files?

Both files are raster-based, dating back to the early days of computer graphics and digital photography. Both also display high-quality images that can be compressed. The main differences between BMP and JPEG are in how they compress image data, display colour and maintain image quality — as well as how they’re typically used.

 

JPEGs are more popular than BMP files these days, mainly due to the widespread use of smartphones and social media where JPEGs are the go-to file type.

 

File sizes. 

JPEGs compress automatically — but the image data that you lose when this happens is barely perceptible to the eye. The JPEG file analyses image information and identifies erasable and compressible details based on the image type. 

 

This process can even reduce JPEG files to 5-10% of their original size. On the other hand, BMP files are generally larger than JPEGs. The intention behind BMPs is to hold as much information as possible. So, while JPEGs can get quite large, BMPs are often bigger.

 

Compression.

As soon as you save an image as a JPEG, it gets compressed. The JPEG compression process is known as lossy— with each subsequent save, change, edit, compression or uncompression, more information gets deleted permanently. Nonetheless, JPEG files often achieve compression of 10:1 with no significant decrease in quality.

 

BMP files are uncompressed. If you want to compress a BMP file, you must do it manually. And if you want to uncompress the image, you’ll be able to restore its full size and detail. The process of compressing and uncompressing BMPs can be slow.

 

Quality.

BMP files generally have a higher quality than JPEGs. In a BMP image, each pixel has its own specific colour. The file may also contain information like colour depth, colour profiles, alpha channels and more. This gives BMP images a higher resolution than JPEG files. Their quality and resolution mean that it’s easier to edit BMP files because there are more pixels you can manipulate. 

 

Use cases.

JPEGs are the most widely used digital image format. Nearly all cameras — both handheld and in smartphones — can take photos as JPEGs. Most scanners do, too. Though JPEG files can be very high-quality, what makes them exceptionally useful is their excellent quality at small sizes. They take up less space in camera memory cards and copy or download faster than BMP files, making them ideal for email attachments, websites, selfies and more.

 

Printing images.

Neither BMP nor JPEG is ideal for printing physical photos. BMP files save and edit images, but don't print well. You can print JPEG images, but they’re better used on the Internet. Files like TIFF and DNG are much better for high-quality printing. If you’re going to print a JPEG file, make sure that you adjust the PPI (pixels per inch).

 

Compatibility.

BMP files will operate most effectively with Microsoft Windows and OS/2 operating systems. If you use Microsoft, BMP files have many built-in advantages. JPEGs are everywhere and highly versatile, no matter what operating system you’re on. They work with a wide array of programmes — on phones, tablets, laptops, digital cameras and more.

 

 

BMP vs. JPEG files: frequently asked questions.

What programme opens BMP files?

You can open BMP files with a range of different programmes. These include Adobe Illustrator and Adobe Photoshop. Simply choose your programme and select your BMP file to open it.

 

Which is larger, a BMP or JPEG file?

Given similar images, a BMP will be larger. But because of limits on dimensions, a BMP can only be as large as 4 GB. There’s no limit to the size of a JPEG. Some satellite photos come in JPEG form, for instance.

 

Do BMP and JPEG files handle colour differently?

JPEG files can support more than 16.77 million colours in each pixel. BMPs are better suited to more limited palettes. Both formats work effectively in black and white.

 

Is BMP lossless?

BMP is generally uncompressed, but you can compress it in a lossless method. This means, in contrast to its lossy JPEG counterpart, it maintains a very high level of detail and definition.

Compare BMPs and JPEGs with other file types.

BMP vs PNG file image

BMP vs. PNG

Learn more about two different compression processes.

JPEG vs RAW file image

JPEG vs. RAW

Discover the differences between the JPEG and RAW file formats.

JPEG vs PNG file image

JPEG vs. PNG

Get to know the compression capabilities of both JPEG and PNG files.

JPEG vs TIFF file image

JPEG vs. TIFF

Find out why JPEGs may work better on the web.