### 28.1.3 Loading images to the legacy format

The readrgb command reads an Xcas image structure (see Section 28.1.1).

- readrgb command takes filename, the name of an image file in JPEG, PNG or GIF format.
- readrgb(filename) returns the legacy Xcas image structure for the image in filename.

#### Example

Assume the the image shown in Figure 28.1 is stored in file image1234.jpg.

> Figure 28.1: An image of size 250× 500 with colors

After reading it into a variable name with readrgb using the legacy Xcas format:

a:=readrgb("image1234.jpg")

the variable a will contain a list.

- a[0] will be [4,250,500], the number of channels, height, and width of the image.
- a[1], the red channel,
- a[2], the green channel,
- a[3], the transparency channel,
- a[4], the blue channel.