imwrite - Write image to graphics file

'bmp'

Windows Bitmap (BMP)

1-bit, 8-bit, and 24-bit uncompressed images

'gif'

Graphics Interchange Format (GIF)

8-bit images

'hdf'

Hierarchical Data Format (HDF4)

8-bit raster image data sets, with or without associated colormap, 24-bit raster image data sets; uncompressed or with RLE or JPEG compression

'jpg' or 'jpeg'

Joint Photographic Experts Group (JPEG)

8-bit, 12-bit, and 16-bit Baseline JPEG images

Note   imwrite converts indexed images to RGB before writing data to JPEG files, because the JPEG format does not support indexed images.

pbm

Portable Bitmap (PBM)

Any 1-bit PBM image, ASCII (plain) or raw (binary) encoding

'pcx'

Windows Paintbrush (PCX)

8-bit images

'pgm'

Portable Graymap (PGM)

Any standard PGM image; ASCII (plain) encoded with arbitrary color depth; raw (binary) encoded with up to 16 bits per gray value

'png'

Portable Network Graphics (PNG)

1-bit, 2-bit, 4-bit, 8-bit, and 16-bit grayscale images; 8-bit and 16-bit grayscale images with alpha channels; 1-bit, 2-bit, 4-bit, and 8-bit indexed images; 24-bit and 48-bit truecolor images; 24-bit and 48-bit truecolor images with alpha channels

'pnm'

Portable Anymap (PNM)

Any of the PPM/PGM/PBM formats, chosen automatically

'ppm'

Portable Pixmap (PPM)

Any standard PPM image. ASCII (plain) encoded with arbitrary color depth; raw (binary) encoded with up to 16 bits per color component

'ras'

Sun Raster (RAS)

Any RAS image, including 1-bit bitmap, 8-bit indexed, 24-bit truecolor and 32-bit truecolor with alpha

'tif' or 'tiff'

Tagged Image File Format (TIFF)

Baseline TIFF images, including 1-bit, 8-bit, 16-bit, and 24-bit uncompressed images, images with packbits compression, images with LZW compression, and images with Deflate compression; 1-bit images with CCITT 1D, Group 3, and Group 4 compression; CIELAB, ICCLAB, and CMYK images

'xwd'

X Windows Dump (XWD)

8-bit ZPixmaps

'BackgroundColor'

A scalar integer that specifies which index in the colormap should be treated as the transparent color for the image and is used for certain disposal methods in animated GIFs. If X is uint8 or logical, indexing starts at 0. If X is double, indexing starts at 1.

'Comment'

A string or cell array of strings containing a comment to be added to the image. For a cell array of strings, a carriage return is added after each row.

'DelayTime'

A scalar value between 0 and 655 inclusive, that specifies the delay in seconds before displaying the next image.

'DisposalMethod'

One of the following strings, which sets the disposal method of an animated GIF: 'leaveInPlace', 'restoreBG', 'restorePrevious', or 'doNotSpecify'.

'Location'

'LoopCount'

A finite integer between 0 and 65535 or the value Inf (the default) which specifies the number of times to repeat the animation. By default, the animation loops continuously. If you specify 0, the animation will be played once. If you specify the value 1, the animation will be played twice, etc.

To enable animation within Microsoft^® PowerPoint^®, specify a value for the 'LoopCount' parameter within the range [1 65535]. Some Microsoft applications interpret the value 0 to mean do not loop at all.

'ScreenSize'

'TransparentColor'

A scalar integer. This value specifies which index in the colormap should be treated as the transparent color for the image. If X (the image) is uint8 or logical, indexing starts at 0. If X is double, indexing starts at 1.

'WriteMode'

'overwrite' (the default) or 'append'. In append mode, imwrite adds a single frame to the existing file.

'Compression'

'none' (the default)

'jpeg'(valid only for grayscale and RGB images)

'rle' (valid only for grayscale and indexed images)

'Quality'

A number between 0 and 100; this parameter applies only if 'Compression' is 'jpeg'.

Higher numbers mean higher quality (less image degradation due to compression), but the resulting file size is larger. The default value is 75.

'WriteMode'

'overwrite' (the default)

'append'

'Bitdepth'

A scalar value indicating desired bitdepth; for grayscale images this can be 8, 12, or 16; for color images this can be 8 or 12.

8 (grayscale) and 8 bit per plane for color images

'Comment'

A column vector cell array of strings or a character matrix. imwrite writes each row of input as a comment in the JPEG file.

Empty

'Mode'

Specifies the type of compression used:'lossy' or 'lossless'

'lossy'

'Quality'

A number between 0 and 100; higher numbers mean higher quality (less image degradation due to compression), but the resulting file size is larger.

75

'Encoding'

One of these strings: 'ASCII' for plain encoding 'rawbits' for binary encoding

'rawbits'

'MaxValue'

A scalar indicating the maximum gray or color value. Available only for PGM and PPM files.

For PBM files, this value is always 1.

Default is 65535 if image array is 'uint16'; 255 otherwise.

'Alpha'

A matrix specifying the transparency of each pixel individually. The row and column dimensions must be the same as the data array; they can be uint8, uint16, or double, in which case the values should be in the range [0,1].

'Author'

A string

'Background'

The value specifies background color to be used when compositing transparent pixels. For indexed images: an integer in the range [1,P], where P is the colormap length. For grayscale images: a scalar in the range [0,1]. For truecolor images: a three-element vector in the range [0,1].

'bitdepth'

A scalar value indicating desired bit depth.

For grayscale images this can be 1, 2, 4, 8, or 16.

For grayscale images with an alpha channel this can be 8 or 16.

For indexed images this can be 1, 2, 4, or 8.

For truecolor images with or without an alpha channel this can be 8 or 16.

By default, imwrite uses 8 bits per pixel, if image is double or uint8; 16 bits per pixel if image is uint16; 1 bit per pixel if image is logical.

'Chromaticities'

An eight-element vector [wx wy rx ry gx gy bx by] that specifies the reference white point and the primary chromaticities

'Comment'

A string

'Copyright'

A string

'CreationTime'

A string

'Description'

A string

'Disclaimer'

A string

'Gamma'

A nonnegative scalar indicating the file gamma

'ImageModTime'

'InterlaceType'

Either 'none' (the default) or 'adam7'

'ResolutionUnit'

Either 'unknown' or 'meter'

'SignificantBits'

A scalar or vector indicating how many bits in the data array should be regarded as significant; values must be in the range [1,BitDepth].

For indexed images: a three-element vector. For grayscale images: a scalar. For grayscale images with an alpha channel: a two-element vector. For truecolor images: a three-element vector. For truecolor images with an alpha channel: a four-element vector.

'Software'

A string

'Source'

A string

'Transparency'

This value is used to indicate transparency information only when no alpha channel is used. Set to the value that indicates which pixels should be considered transparent. (If the image uses a colormap, this value represents an index number to the colormap.)

For indexed images: a Q-element vector in the range [0,1], where Q is no larger than the colormap length and each value indicates the transparency associated with the corresponding colormap entry. In most cases, Q = 1.

For grayscale images: a scalar in the range [0,1]. The value indicates the grayscale color to be considered transparent.

For truecolor images: a three-element vector in the range [0,1]. The value indicates the truecolor color to be considered transparent.

Note   You cannot specify 'Transparency' and 'Alpha' at the same time.

'Warning'

A string

'XResolution'

A scalar indicating the number of pixels/unit in the horizontal direction

'YResolution'

A scalar indicating the number of pixels/unit in the vertical direction

'Alpha'

A matrix specifying the transparency of each pixel individually; the row and column dimensions must be the same as the data array; can be uint8, uint16, or double. Can only be used with truecolor images.

Empty matrix ([])

'Type'

One of these strings: 'standard' (uncompressed, b-g-r color order with truecolor images) 'rgb' (like 'standard', but uses r-g-b color order for truecolor images) 'rle' (run-length encoding of 1-bit and 8-bit images)

'standard'

'ColorSpace'

Specifies the color space used to represent the color data. 'rgb' 'cielab' 'icclab' ¹ (default is 'rgb').

Note: To use the CMYK color space in a TIFF file, do not use the 'ColorSpace' parameter. It is sufficient to specify an M-by-N-by-4 input array.

'Compression'

'none'
'packbits' (default for non-binary images)
'lzw'
'deflate'
'jpeg'
'ccitt' (binary images only; default)
'fax3' (binary images only)
'fax4' (binary images only)

Note: 'jpeg' is a lossy compression scheme; other compression modes are lossless. Also, if you specify 'jpeg' compression, you must specify the 'RowsPerStrip' parameter and the value must be a multiple of 8.

'Description'

Any string; fills in the ImageDescription field returned by imfinfo. By default, the field is empty.

'Resolution'

A two-element vector containing the XResolution and YResolution, or a scalar indicating both resolutions. The default value is 72.

'RowsPerStrip'

A scalar value specifying the number of rows to include in each strip. The default will be such that each strip is about 8K bytes.

Note: You must specify the 'RowsPerStrip' parameter if you specify 'jpeg' compression. The value must be a multiple of 8.

'WriteMode'

'overwrite' (default)

'append'

8-bit ICCLAB

Represents values as integers in the range [0 255]. L* values are multiplied by 255/100. 128 is added to both the a* and b* values.

'icclab'

8-bit ICCLAB

'cielab'

8-bit CIELAB

16-bit ICCLAB

Represents the values as integers in the range [0, 65280]. L* values are multiplied by 65280/100. 32768 is added to both the a* and b* values, which are represented as integers in the range [0,65535].

'icclab'

16-bit ICCLAB

'cielab'

16-bit CIELAB

Double-precision 1976 CIE L*a*b* values

L* is in the dynamic range [0, 100]. a* and b* can take any value. Setting a* and b* to 0 (zero) produces a neutral color (gray).

'icclab'

8-bit ICCLAB

'cielab'

8-bit CIELAB