---
title: Image I/O
framework: imageio
role: collection
role_heading: Framework
path: imageio
---

# Image I/O

Read and write most image file formats, and access an image’s metadata.

## Overview

Overview The Image I/O framework allows applications to read and write most image file formats. This framework offers high efficiency, color management, and access to image metadata. For more information, see Image I/O Programming Guide.

## Topics

### Image Management

- [CGImageSource](imageio/cgimagesource.md)
- [CGImageDestination](imageio/cgimagedestination.md)

### XMP Metadata

- [CGImageMetadata](imageio/cgimagemetadata.md)
- [CGMutableImageMetadata](imageio/cgmutableimagemetadata.md)
- [CGImageMetadataTag](imageio/cgimagemetadatatag.md)
- [XMP Namespaces and Prefixes](imageio/xmp-namespaces-and-prefixes.md)
- [kCFErrorDomainCGImageMetadata](imageio/kcferrordomaincgimagemetadata.md)
- [CGImageMetadataErrors](imageio/cgimagemetadataerrors.md)

### Common Image Properties

- [Image Properties](imageio/image-properties.md)
- [EXIF Dictionary Keys](imageio/exif-dictionary-keys.md)
- [IPTC Dictionary Keys](imageio/iptc-dictionary-keys.md)
- [GPS Dictionary Keys](imageio/gps-dictionary-keys.md)
- [WebP Data](imageio/webp-data.md)

### Format-Specific Properties

- [CIFF Image Properties](imageio/ciff-image-properties.md)
- [DNG Image Properties](imageio/dng-image-properties.md)
- [GIF Image Properties](imageio/gif-image-properties.md)
- [HEIC Image Properties](imageio/heic-image-properties.md)
- [JFIF Image Properties](imageio/jfif-image-properties.md)
- [PNG Image Properties](imageio/png-image-properties.md)
- [TGA Image Properties](imageio/tga-image-properties.md)
- [TIFF Image Properties](imageio/tiff-image-properties.md)
- [8BIM Image Properties](imageio/8bim-image-properties.md)

### Manufacturer-Specific Properties

- [Nikon Camera Dictionary Keys](imageio/nikon-camera-dictionary-keys.md)
- [Canon Camera Dictionary Keys](imageio/canon-camera-dictionary-keys.md)
- [kCGImagePropertyMakerAppleDictionary](imageio/kcgimagepropertymakerappledictionary.md)
- [kCGImagePropertyMakerMinoltaDictionary](imageio/kcgimagepropertymakerminoltadictionary.md)
- [kCGImagePropertyMakerFujiDictionary](imageio/kcgimagepropertymakerfujidictionary.md)
- [kCGImagePropertyMakerOlympusDictionary](imageio/kcgimagepropertymakerolympusdictionary.md)
- [kCGImagePropertyMakerPentaxDictionary](imageio/kcgimagepropertymakerpentaxdictionary.md)
- [kCGImagePropertyRawDictionary](imageio/kcgimagepropertyrawdictionary.md)

### Spatial Photos

- [Writing spatial photos](imageio/writing-spatial-photos.md)
- [Creating spatial photos and videos with spatial metadata](imageio/creating-spatial-photos-and-videos-with-spatial-metadata.md)

### Animations

- [CGAnimateImageAtURLWithBlock(_:_:_:)](imageio/cganimateimageaturlwithblock(_:_:_:).md)
- [CGAnimateImageDataWithBlock(_:_:_:)](imageio/cganimateimagedatawithblock(_:_:_:).md)
- [CGImageSourceAnimationBlock](imageio/cgimagesourceanimationblock.md)
- [kCGImageAnimationStartIndex](imageio/kcgimageanimationstartindex.md)
- [kCGImageAnimationDelayTime](imageio/kcgimageanimationdelaytime.md)
- [kCGImageAnimationLoopCount](imageio/kcgimageanimationloopcount.md)
- [CGImageAnimationStatus](imageio/cgimageanimationstatus.md)

### Reference

- [Image I/O Constants](imageio/image-i-o-constants.md)
- [Image I/O Functions](imageio/image-i-o-functions.md)
- [Image I/O Macros](imageio/image-i-o-macros.md)

### Variables

- [kCGComputeHDRStats](imageio/kcgcomputehdrstats.md)
- [kCGImageDestinationEncodeAlternateColorSpace](imageio/kcgimagedestinationencodealternatecolorspace.md)
- [kCGImageDestinationEncodeBaseColorSpace](imageio/kcgimagedestinationencodebasecolorspace.md)
- [kCGImageDestinationEncodeBaseIsSDR](imageio/kcgimagedestinationencodebaseissdr.md)
- [kCGImageDestinationEncodeBasePixelFormatRequest](imageio/kcgimagedestinationencodebasepixelformatrequest.md)
- [kCGImageDestinationEncodeGainMapPixelFormatRequest](imageio/kcgimagedestinationencodegainmappixelformatrequest.md)
- [kCGImageDestinationEncodeGainMapSubsampleFactor](imageio/kcgimagedestinationencodegainmapsubsamplefactor.md)
- [kCGImageDestinationEncodeGenerateGainMapWithBaseImage](imageio/kcgimagedestinationencodegenerategainmapwithbaseimage.md)
- [kCGImageDestinationEncodeIsBaseImage](imageio/kcgimagedestinationencodeisbaseimage.md)
- [kCGImageDestinationEncodeRequest](imageio/kcgimagedestinationencoderequest.md)
- [kCGImageDestinationEncodeRequestOptions](imageio/kcgimagedestinationencoderequestoptions.md)
- [kCGImageDestinationEncodeToISOGainmap](imageio/kcgimagedestinationencodetoisogainmap.md)
- [kCGImageDestinationEncodeToISOHDR](imageio/kcgimagedestinationencodetoisohdr.md)
- [kCGImageDestinationEncodeToSDR](imageio/kcgimagedestinationencodetosdr.md)
- [kCGImageDestinationEncodeTonemapMode](imageio/kcgimagedestinationencodetonemapmode.md)
- [kCGImagePropertyASTCBlockSize](imageio/kcgimagepropertyastcblocksize.md)
- [kCGImagePropertyASTCBlockSize4x4](imageio/kcgimagepropertyastcblocksize4x4.md)
- [kCGImagePropertyASTCBlockSize8x8](imageio/kcgimagepropertyastcblocksize8x8.md)
- [kCGImagePropertyASTCEncoder](imageio/kcgimagepropertyastcencoder.md)
- [kCGImagePropertyBCEncoder](imageio/kcgimagepropertybcencoder.md)
- [kCGImagePropertyBCFormat](imageio/kcgimagepropertybcformat.md)
- [kCGImagePropertyEncoder](imageio/kcgimagepropertyencoder.md)
- [kCGImagePropertyOpenEXRCompression](imageio/kcgimagepropertyopenexrcompression.md)
- [kCGImagePropertyPVREncoder](imageio/kcgimagepropertypvrencoder.md)
- [kCGImageProviderPreferredTileHeight](imageio/kcgimageproviderpreferredtileheight.md)
- [kCGImageProviderPreferredTileWidth](imageio/kcgimageproviderpreferredtilewidth.md)
- [kCGImageSourceAllowableTypes](imageio/kcgimagesourceallowabletypes.md)
- [kCGImageSourceGenerateImageSpecificLumaScaling](imageio/kcgimagesourcegenerateimagespecificlumascaling.md)