Chapitre 6. Enregistrer les images avec GIMP

Chapitre 6. Enregistrer les images avec GIMP
	Partie II. Du débutant à l’expert

Table des matières

1.1. Enregistrer / Exporter des images
1.2. Formats de fichiers

2. Préparer vos images pour Internet

2.1. Images avec un rapport Taille/Qualité optimal
2.2. Réduire encore plus la taille du fichier
2.3. Enregistrer des images avec transparence

1. Fichiers

GIMP is capable of reading and writing a large variety of graphics file formats. With the exception of GIMP's native XCF file format, file handling is done by plug-ins. This makes it relatively easy to extend GIMP to support new file types when the need arises.

1.1. Enregistrer / Exporter des images

	Note
When you open an image, let's say in JPG or PNG file format, it is imported into GIMP's own XCF format, as a new project. For example, a « sunflower.png » image will be loaded as « [sunflower] (imported)-1.0 (indexed color, 1 layer) ». The leading asterisk indicates that this file has been changed. This image can be saved as « sunflower.xcf » by using the Save* command. If you need your image in another format, you should use the Export command.

Note

When you open an image, let's say in JPG or PNG file format, it is imported into GIMP's own XCF format, as a new project.

For example, a « sunflower.png » image will be loaded as « *[sunflower] (imported)-1.0 (indexed color, 1 layer) ». The leading asterisk indicates that this file has been changed. This image can be saved as « sunflower.xcf » by using the Save command. If you need your image in another format, you should use the Export command.

When you are finished working with an image, you will save the results. In fact, it is often a good idea to save at intermediate stages too. GIMP is a pretty robust program, but on rare occasions crashes have happened.

GIMP's native format XCF is special. It is the only format that can store everything about an image (with the exception of « undo » information). This is the reason that saving can only be done in this format. It makes the XCF format especially suited for storing intermediate results, and for saving images to be re-opened later in GIMP.

XCF files are not readable by most other programs that display images. Once you have finished editing your image, you can export it to the format of your choice. GIMP supports a wide range of formats. Most file formats that can be imported, can also be used for exporting.

1.2. Formats de fichiers

There are several commands for saving and exporting images. They are listed in the section covering the File Menu. More information on how to use them can be found there.

GIMP permet d’exporter les images crées dans un grand nombre de formats variés. Il est important de comprendre que le seul format capable d’enregistrer toutes les informations sur une image y compris les calques, la transparence, etc…, est le format natif XCF de GIMP. Chacun des autres formats conserve certaines propriétés et perdent les autres. C’est à vous de comprendre les possibilités du format choisi.

L’exportation ne modifie pas l’image présente sur votre écran et n’entraîne aucune perte d’information. Voyez Exporter des fichiers.

	Note
Lorsque vous fermez une image (par exemple en quittant GIMP), vous êtes prévenu si l’image a été modifiée sans être enregistrée (un astérisque figure en tête du nom d’image). Figure 6.1. Avertissement de fermeture Saving an image in GIMP's native format XCF will cause the image to be considered "not dirty". On the contrary, exporting an image will not change it to "not dirty", because GIMP can't know for sure that no image information will be lost.

Note

Lorsque vous fermez une image (par exemple en quittant GIMP), vous êtes prévenu si l’image a été modifiée sans être enregistrée (un astérisque figure en tête du nom d’image).

Figure 6.1. Avertissement de fermeture

Saving an image in GIMP's native format XCF will cause the image to be considered "not dirty". On the contrary, exporting an image will not change it to "not dirty", because GIMP can't know for sure that no image information will be lost.