16 Working with Images and Media

Overview

In modern Android apps, images and media are central to how users experience your application. Photos, icons, illustrations, music, podcasts, and videos all help communicate information and feeling much faster than text alone. For a beginner, working with media can seem intimidating, because it involves both visual design and technical concerns such as file formats, performance, and user permissions. This chapter provides a high level view of what it means to handle images and media on Android, and prepares you for the specific topics that follow.

You will see where images come from, how they are stored inside your app, how they are loaded efficiently, and how audio and video can be played in a way that respects device resources and user expectations. The details of ImageView, drawables, loading images from the internet, and audio or video playback are covered in their dedicated subsections, so here you will focus on concepts and the bigger picture.

Media Types in Android Apps

Android applications typically deal with three broad categories of media: images, audio, and video. These all share some common ideas, such as file formats and compression, but they are used in different ways.

Images are everywhere in Android interfaces. They include app icons, toolbar icons, logos, illustrations, thumbnails, and background pictures. An image in Android is usually represented in the UI by an ImageView, and the actual bitmap or vector data is stored in a resource or loaded at runtime. Image files often use formats like PNG and JPEG for bitmaps, or XML and SVG for vectors. Choosing between them is an important part of media design in Android, especially for performance and appearance on different screen densities.

Audio in Android covers sound effects, notification sounds, voice recordings, music, and spoken content like podcasts or audio books. Unlike images, which are usually static on screen, audio is time based and must be streamed or decoded as it plays. Formats include MP3, AAC, OGG, and WAV. Android provides player APIs that decode these formats and manage playback state, such as play, pause, and stop. You will see later how to integrate audio in a way that is responsive and respectful of battery and memory usage.

Video combines moving images with optional audio, and is the most resource intensive media type. Video playback in Android must account for screen size, orientation changes, buffering from the network, and user controls like seeking within the video. Video files come in containers such as MP4 or WebM, which bundle encoded audio and video streams together. Android has components for embedding a video player in your layouts and for working with full screen playback.

Understanding these categories helps you decide what API or UI component is appropriate for the task. For example, a static icon uses a drawable image, a short feedback sound uses a lightweight sound effect API, and a long movie uses a more advanced video player.

Working with Media Resources

Media in Android does not live in a single place. Some assets are bundled inside your application package, and others are accessed from outside storage or from the internet. This separation influences how your app is structured and how you write code.

Bundled media resources are included at build time. These are usually static files that ship with your app, such as icons, background images, placeholder graphics, and short sound files. You define them in res subdirectories, for example res/drawable for images, and then reference them from your layouts and Kotlin code using generated resource identifiers. Because these files live inside the application package, they are always available even when the device is offline, and they are read only at runtime.

External media resides outside of your application package. This includes photos taken by the user, audio recordings created in the app, or files that the user has stored on shared storage or in the cloud. Accessing these resources can require permissions and user consent, because they may be personal and sensitive. When you work with external media, you also have to handle cases where a file is not available or is too large to load in memory at once.

A third category is remote media. In many apps, images, songs, or videos are stored on servers, and your app only downloads what it needs when it is needed. This is common for social networks, news feeds, and streaming services. Remote media access always involves networking and usually some form of caching so that content does not need to be reloaded constantly. Later, when you explore loading images from the internet, you will learn how to combine network requests, local caching, and background loading to present media smoothly.

All three locations bundled, external, and remote media are important when planning an app. A simple offline application might rely only on bundled drawables, while a media rich social application will use all three and will need a careful design for storage and permissions.

Performance, Memory, and Quality

Media is visually impressive, but it can also be heavy. Large images and long audio or video files can quickly consume memory, battery, and network bandwidth if they are not handled correctly. Learning some basic performance principles early will save you problems as your apps grow.

Images can be deceptive. A photo file may not look large on disk, but when it is loaded into memory as a bitmap it can occupy much more space. For example, a 4000 by 3000 pixel image contains 12 million pixels. If you represent each pixel with 4 bytes in memory, the bitmap requires about 48 megabytes. On a device with limited RAM, a few such images can cause performance problems or even application crashes. To avoid this, you should display images at sizes that match the view where they appear, and you should decode them with scaling when needed. Libraries that you will see later assist with this scaling automatically.

Network performance is especially important for remote images and media. Large image files or high resolution videos can take a long time to load on slow connections, and they consume user data. Compressing images, using appropriate resolutions, and caching content locally are standard techniques. For audio and video, streaming and buffering allow playback to begin before the entire file is downloaded, which improves user experience.

Battery life is another important concern. Continuous media playback, particularly video, can use significant power. Efficient decoding, using hardware acceleration where possible, and properly releasing media resources when playback stops are all part of responsible media handling. You will also need to consider how playback should behave when the app is in the background or when the screen is off.

Balancing quality and performance is an ongoing task. A very small compressed image loads quickly but might look blurry, while a very large image looks sharp but can slow down rendering and scrolling. The right choice depends on your app’s design and the expectations of your users.

User Experience with Images and Media

Media is not only about technical implementation. It directly affects how users perceive and interact with your app. A thoughtful approach to images and media can make your app feel more intuitive, faster, and more delightful to use.

Images often guide navigation and meaning. Icons in toolbars or buttons communicate actions quickly, and thumbnails help users recognize content at a glance. Consistent styles, clear shapes, and accessible contrast levels all contribute to a better experience. When you add or change images, always consider how they will appear on different screen sizes and under themes such as light or dark mode.

With remote images and videos, loading time is a key part of the experience. Blank areas or sudden jumps in the layout can confuse users. Showing placeholders while content loads, using subtle fade in animations when an image becomes available, and preserving the layout space even when data is not yet loaded all give a sense of stability. Later, when you explore loading images from the internet, you will learn how to combine placeholder resources with asynchronous loading so that scrolling remains smooth.

Audio and video interfaces must respect the user’s environment. Users may be in a quiet place, or they may be listening on headphones. Providing clear controls for play, pause, and volume, and reacting properly to system events like incoming calls or audio focus changes, helps your app behave in a way that feels natural and polite. It is also important to communicate when audio is playing in the background, for example through notifications, so that users can find and control it easily.

Accessibility is closely tied to media. For example, images that are purely decorative should not distract screen reader users, while meaningful images should have descriptions. For video, captions and subtitles can make content usable for people who are deaf or hard of hearing. Designing media use with accessibility in mind will make your applications usable by a wider audience.

Permissions, Privacy, and Legal Considerations

Working with media often involves user data or third party content, which introduces privacy and legal responsibilities. Files such as personal photos, recorded conversations, and private videos are sensitive, and users expect applications to respect their choices.

On Android, accessing user media, especially from shared storage, usually requires runtime permissions. The system asks the user for consent the first time your app tries to read or write certain types of media. You must always explain in your app why such access is needed, and you must handle the case where the user denies permission. For example, if your app is designed to choose a photo from the gallery, you should provide an alternative message or flow when access is not granted.

Media can also contain personal information indirectly, such as identifiable faces, locations, and background details. When you upload media from the device to your servers, you should clearly communicate to users what is being shared and why. Storing media securely, transmitting it over encrypted connections, and respecting user deletion requests are all part of safe media handling.

Legal concerns also apply. Images, songs, and videos are often protected by copyright. You must ensure that any media you bundle with your app or load from the internet is used according to its license. Using stock images, open licenses, or content that you own is safer than copying media you find randomly online. Some media formats also involve patents or licensing for codecs, although Android devices usually provide system level support for common formats.

How Images and Media Fit into the Rest of the Course

The sections that follow this overview focus on the practical parts of working with media in Android. First, you will learn about ImageView and drawable resources. This will show you how to place images in your layouts, how to choose appropriate image resources, and how to work with vectors and bitmaps. You will see how images are referenced from XML and from Kotlin code using resource identifiers.

Next, you will learn how to load images from the internet. This will connect your understanding of media with networking concepts that you encounter elsewhere in the course. You will see how to load images asynchronously so that your UI remains responsive, how to cache results for better performance, and how to handle errors such as missing or slow network connections.

Then, you will explore audio and video playback. This part will introduce you to Android’s media player components, show you how to control playback state, and demonstrate how to integrate media controls into your user interface. You will also see how media playback interacts with the activity lifecycle and with background execution, topics that connect to other chapters such as background tasks and services.

By the end of this group of lessons, you will be able to design apps that present rich visual content, load and display remote images efficiently, and play audio or video content in a way that is reliable and respectful of device resources. This will prepare you for more advanced topics later in the course, such as custom views, adaptive UIs, and more complex media experiences.