Image Loading Libraries in Android

Image loading is an important part of Android app development. Applications frequently display images from the internet, local storage, or application resources. Image loading libraries help developers load, resize, cache, and display these images efficiently without writing complex image-processing code.

• Image loading libraries handle image downloading, decoding, resizing, and caching.
• They help reduce memory usage, avoid unnecessary network requests, and improve scrolling performance.
• Glide, Coil, and Fresco are suitable for modern Android applications, while Picasso and Universal Image Loader are primarily relevant to older projects.

Image Loading Libraries in Android

Image loading libraries are tools that simplify fetching, processing, caching, and displaying images in Android applications. Without these libraries, developers may need to manage network requests, background processing, bitmap decoding, memory usage, and caching manually.

For example, an e-commerce application displays multiple product images. Instead of downloading each image whenever the user scrolls, an image loading library can reuse cached images and manage loading requests efficiently.

Image Loading Libraries for Android

The following libraries provide different approaches to handling image loading in Android applications.

1. Glide

Glide is an open-source image loading and caching library developed by Bumptech. It is designed to load images efficiently, particularly in applications that display large image collections or scrolling lists.

Glide automatically handles image decoding, memory and disk caching, resource reuse, and request lifecycle management.

Key Features:

• Supports images, animated GIFs, and video thumbnails.
• Provides memory and disk caching to reduce repeated image loading.
• Supports image resizing, cropping, and transformations.
• Integrates with Android components to manage loading requests.
• Optimizes image loading for scrolling lists such as RecyclerView.

Glide Dependency

Open the app-level build.gradle.kts file and add:

dependencies {
implementation("com.github.bumptech.glide:glide:5.0.9")
}

Example: Loading an Image Using Glide

Glide.with(this)
.load("https://example.com/image.jpg")
.placeholder(R.drawable.placeholder)
.error(R.drawable.error_image)
.into(imageView);

Explanation:

• with(this) provides the Android lifecycle context.
• load() specifies the image URL.
• placeholder() displays a temporary image during loading.
• error() displays a fallback image if loading fails.
• into() displays the loaded image in an ImageView.

Best Suited For: Applications with image-heavy interfaces, product catalogs, photo galleries, and scrolling image lists.

2. COIL (Coroutine Image Loader)

Coil is a Kotlin-first image loading library built around Kotlin Coroutines. It provides a simple and efficient way to load images in Android applications and supports Jetpack Compose.

Coil is particularly useful for Kotlin-based projects because it integrates naturally with coroutines and modern Android UI development.

Key Features:

• Built using Kotlin and Kotlin Coroutines.
• Supports memory and disk caching.
• Provides convenient APIs for Jetpack Compose and Android Views.
• Supports image transformations and configurable loading requests.
• Offers optional modules for formats such as GIF and SVG.

Coil Dependency

For projects using Jetpack Compose, add:

dependencies {
implementation("io.coil-kt.coil3:coil-compose:3.6.3")
implementation("io.coil-kt.coil3:coil-network-okhttp:3.6.3")
}

For projects using traditional Android Views, use io.coil-kt.coil3:coil instead of coil-compose.

Example: Loading an Image Using Coil in Jetpack Compose

@Composable
fun ProductImage() {
AsyncImage(
model = "https://example.com/product.jpg",
contentDescription = "Product image",
modifier = Modifier.size(150.dp)
)
}

Explanation:

• AsyncImage loads and displays the requested image asynchronously.
• model specifies the image source.
• contentDescription provides a description for accessibility.
• Modifier.size() defines the image component's size.

Best Suited For: Kotlin-based Android applications, Jetpack Compose projects, and applications requiring a concise image loading API.

3. Fresco

Fresco is an image management library developed by Meta. It provides an image pipeline for downloading, decoding, caching, and displaying images while offering extensive control over image processing and memory management.

Fresco is useful for applications that require advanced image handling, customizable caching, or progressive image rendering.

Key Features:

• Provides memory and disk caching.
• Supports progressive JPEG image rendering.
• Supports animated GIF and WebP images through appropriate modules.
• Offers customizable image decoding and processing pipelines.
• Includes tools for handling complex image loading requirements.

Fresco Dependency

Add the following dependency to build.gradle.kts:

dependencies {
implementation("com.facebook.fresco:fresco:3.9.0")
}

Example: Loading an Image Using Fresco

Fresco provides the SimpleDraweeView component for displaying images in existing applications.

Uri imageUri =
Uri.parse("https://example.com/image.jpg");
SimpleDraweeView imageView =
findViewById(R.id.my_image_view);
imageView.setImageURI(imageUri);

The example assumes that Fresco has been initialized and my_image_view is a SimpleDraweeView defined in the XML layout.

Note: SimpleDraweeView is deprecated in Fresco's current source code in favor of VitoView. It is shown here for understanding existing Fresco implementations. New projects should consult the current Fresco documentation before selecting a view API.

Best Suited For: Applications that require advanced image processing, progressive JPEG support, and fine-grained image pipeline control.

4. Picasso

Picasso is an image downloading and caching library developed by Square. It became popular because of its simple API, allowing developers to load images from URLs with very little code.

Picasso supports basic image downloading, caching, resizing, and transformations.

Key Features:

• Provides a simple API for loading images.
• Supports automatic memory caching.
• Supports image resizing and transformations.
• Provides placeholder and error images.
• Requires minimal configuration for basic image loading operations.

Picasso Dependency

dependencies {
implementation("com.squareup.picasso:picasso:2.8")
}

Example: Loading an Image Using Picasso

Picasso.get()
.load("https://example.com/image.jpg")

.placeholder(R.drawable.placeholder)
.error(R.drawable.error_image)
.into(imageView);

This code downloads an image and displays it in an ImageView. Picasso handles downloading and caching internally.

Maintenance Status: Picasso is officially deprecated. Its maintainers recommend using alternatives such as Coil for new projects and planning migration for existing applications. No further public Maven Central releases are planned.

Best Suited For: Maintaining existing Android applications that already depend on Picasso.

Picasso vs Glide: The main difference between Glide and Picasso is caching. Let's see how both react. If one loads an image with different sizes on different screens. For example, a profile picture can be smaller on top of all screens but bigger in the profile section. 

• If one loads it with Glide, it keeps 2 copies of the same image with different sizes.
• Picasso keeps only one max size of the image and renders it on run time.

5. UIL (Universal Image Loader)

Universal Image Loader is an older Android image loading library that provides configurable options for loading, caching, and displaying images. It was widely used before newer solutions such as Glide and Coil became common.

UIL allows developers to control different aspects of image loading, including threading, caching, and image display behavior.

Key Features:

• Supports asynchronous and synchronous image loading.
• Provides configurable memory and disk caching.
• Supports custom image downloading and decoding configurations.
• Offers image loading callbacks.
• Supports configurable placeholders and display options.

UIL Dependency

dependencies {
implementation(
"com.nostra13.universalimageloader:universal-image-loader:1.9.5"
)
}

Example: Loading an Image Using UIL

ImageLoader.getInstance().displayImage(
"https://example.com/image.jpg",
imageView
);

This example assumes the UIL ImageLoader singleton has already been initialized with an appropriate configuration.

Maintenance Status: UIL is no longer actively maintained. Its maintainer announced the end of development in November 2015, and version 1.9.5 remains its final published release. It is not recommended for new Android projects.

Best Suited For: Understanding or maintaining legacy Android applications that already use UIL.

How to Choose an Image Loading Library in Android?

Choosing an image loading library depends on the application's programming language, UI framework, image requirements, and existing dependencies.

• Choose Glide when building image-heavy applications, photo galleries, or scrolling lists using Android Views.
• Choose Coil for Kotlin applications, especially those using Jetpack Compose.
• Choose Fresco when the application needs advanced image pipeline customization or progressive JPEG rendering.
• Continue using Picasso only when maintaining an existing application, while considering migration to a maintained alternative.
• Avoid UIL for new applications because it no longer receives maintenance updates.

For most new Android projects, Glide and Coil are practical starting points. Fresco is worth considering when the application's image management requirements justify its more specialized pipeline.