A disadvantage of GIF is that it only supports colours. The risk of losing quality when compressing a GIF file is large, especially for colourful images. Nowadays GIF is used on the web, mainly for simple animations.
PNG, originally created as an improved replacement for GIF, is a popular format used by photographers and graphic designers. PNG files can also be shared on the web. One of the best features of PNG is that it has transparency options. You can easily overlay a PNG image into a background usually represented by a white-and-gray checkerboard , maintaining transparency and giving the overall photo or graphics a 3D quality. This feature also allows more efficient images editing; photo editors and graphic designers can easily apply their edits in layers.
So, what is a PSD file used for? PSD files are the primary format for artwork and images created in Adobe Photoshop. This is a favorite working format for designers and photographers. But beware, opening and editing a psd will require the Adobe Photoshop to be installed on your computer. Advertising Cloud. Audience Manager. Campaign Standard. Experience Cloud. Experience Manager. Experience Platform. View all communities. Feedback Panel. View your awards after completing your profile.
Adobe Experience League. Exit search. Extract Text - Extracts the text so that users can search for text in a Viewer. The file opens in Detail View. Resources on adobe. On this page. View next:. All Learning. Documentation home. Color mode data is available only for indexed color and duotone as defined by the mode field in the File Header section.
For all other modes, this section is represented by 4-byte zeroed values. For Indexed color images, the length is and the color data contains the color table for the image, in non-interleaved order. For Duotone images, color data contains the duotone specification the format of which is not documented. Other applications that read Photoshop files can treat a duotone image as a gray image, and just preserve the contents of the duotone information when reading and writing the file.
The third section of the file contains image resources. It starts with a length field, followed by a series of resource blocks. Image resources are used to store non-pixel data associated with images such as pen tool paths.
The basic structure of image resource blocks is as shown below:. The fourth section of a Photoshop file contains information about layers and masks such as number of layers, channels in the layers, blending ranges, adjustment layer keys, effects layers, and mask parameters. If there are no layers or masks, this section is represented by zeroed 4-byte field. Special attention needs to be paid to the length of sections while reading this section due to the zeroed values.
The arrangement of Layer and Mask section is as follow:. The image pixel data is contained in the Image Data section of the file. Arrangement of data in Image Data section is in planar order i.
Each plane is stored in scan-line order, with no pad bytes, The image data section is arrange in a format as shown in the following table. Table of Content.
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