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Import bitmap images

Learn about bitmap images and how to import them in Adobe Illustrator.

About bitmap images

Bitmap images, technically called raster images, use a rectangular grid of picture elements (pixels) to represent images. Each pixel is assigned a specific location and color value. You edit pixels rather than objects or shapes when you work with bitmap images. Bitmap images are the most common electronic medium for continuous-tone images, such as photographs or digital paintings, because they can more efficiently represent subtle gradations of shades and color.

Bitmap images are resolution-dependent because they contain a fixed number of pixels. As a result, they can lose detail and appear jagged if scaled to high magnifications on‑screen or printed at a lower resolution than they were created for.

Bitmap image at different levels of magnification
Example of a bitmap image at different levels of magnification

Pastaba:

In Adobe Illustrator, you can create bitmap effects in your artwork using effects and graphic styles.

To learn how to import or place bitmap images, see Place multiple files.

Image resolution guidelines for final output

Bitmap images contain a fixed number of pixels, usually measured in pixels per inch (ppi). An image with a high resolution contains more, and therefore smaller, pixels than an image of the same printed dimensions with a low resolution. For example, a 1‑inch‑by‑1‑inch image with a resolution of 72 ppi contains a total of 5184 pixels (72 pixels wide x 72 pixels high = 5184). The same 1‑inch‑by‑1‑inch image with a resolution of 300 ppi would contain a total of 90,000 pixels.

For imported bitmap images, image resolution is determined by the source file. For bitmap effects, you can specify a custom resolution. To determine the image resolution to use, consider the medium of final distribution for the image.

The following guidelines can help you determine your requirements for image resolution:

Commercial printing

It requires 150 to 300 ppi (or more) images, depending on the press (dpi) and screen frequency (lpi) you’re using. Always consult with your prepress service provider before making production decisions, as commercial printing requires large, high-resolution images.

Desktop printing

Desktop printing usually requires images within the range of 72 ppi (for photographs printed on a 300 ppi printer) to 150 ppi (for photographs printed on devices up to 1000 ppi). For line art (1‑bit images), make sure that the resolution of your graphics matches the resolution of the printer.

Web publishing

Online publishing generally requires images with pixel dimensions that fit the intended monitor. The images are usually less than 500 pixels wide and 400 pixels tall to leave room for browser window controls or such layout elements as captions. Creating an original image at a screen resolution of 96 ppi for Windows–based images and 72 ppi for macOS–based images lets you view the image as it will likely appear when viewed from a typical web browser. When you’re publishing online, the only times you’re likely to need resolutions above those ranges are when you want viewers to zoom in for more detail in a PDF document or when you’re producing a document for printing on demand.

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