Using images as resources

In order that the candidate's examination experience is as smooth as possible, it is important that any images used for resources are of a suitable standard. Here we've provided some detailed guidance for the use of images in risr/ assess.

Types of image resources

Images come in a variety of file formats, some are recommended and supported, however, there are some that we do not recommend or do not support for use in your exam.

The exact image type will depend on a few factors about how it may be used in a question. Key considerations are:

• Detail and Zoom: Ensure users can see necessary details and zoom in if needed. e.g. graphs or scan content for inspection.
• File Size and Download Speed: Optimise image size for quick downloading.
• Presentation Method: Consider how the image will be displayed (e.g., on paper or a device screen).

Image Optimisation Guide

Compression	Refers to file size	Compressing images reduces file size, aiding upload and download speed. Smaller file sizes ensure quick downloads. Over-compression can degrade image quality, causing blurriness ( a form of pixelation).
Pixel Dimensions	Refers to size of image in pixels (x and y dimensions)	Different outputs display varying pixels per inch/centimetre. Compression may reduce quality without changing pixel count, but detail loss is likely. More pixels mean larger file sizes. Reducing pixel size increases speed but decreases quality, making images appear blocky (another form of pixelation).
Aspect Ratio	Refers to the proportion of width to height	Altering width or height changes the image proportion and can cause distortion. Cropping an image to remove negative space may change the aspect ratio and unintentionally emphasise certain areas. HD TV dimensions: 1920 x 1080 (width by height).
Resolution	Refers to quality, measured in dpi (dots per inch)	Affects display size but is independent of image dimensions. 300dpi is ideal for print and online zoom. For web viewing, 72dpi is sufficient, but zooming will be less effective. Higher resolution allows better detail but increases file size.

In the browser app, candidates always have the option to expand the image to larger proportions so please consider this when supplying images of sufficient quality. A thumbnail image is unlikely to look good expanded. 

Recommended and Supported Image File Types

File Type	Recommended	Supported	Description
PNG	✓	✓	Best for graphical images. Can have a transparent background where necessary.
JPEG	✓	✓	Compressed image files, ideal for photographic images. Quality can be adjusted from low to high, balancing quality and file size.
DICOM	✓	✓	DICOM images are multi-slice images that are highly compressed but produce a quality multi-slice image. The file sizes are large and best used to display X-Rays, CT Scans, etc. For more detailed guidelines on DICOM images, refer to the article on DICOM resources.
MP4	✓	✓	Video file format used for various multimedia.
PDF	✗	✓	Usually document files but can include images. Embedding in HTML or Word exports isn’t available, but supported on iPad or P4B. Images in PDFs are often embedded as other formats.
TIFF (TIF)	✗	✓	Generally uncompressed, leading to large file sizes and slow upload/download times. You may want to keep these as a reference or master resource and create a good quality JPEG version for use in an exam. Because of the size issue, these file types are not recommended and appear with a warning when creating the Resource in DRAFT state and when viewing in the Resource Library.
GIF	✗	✗	Useful for moving images with repeating motion, online images and logos. Suitable for web display. Not supported in risr/ assess.
HEIC	✗	✗	Apple-specific format found on mobile devices. High quality with advanced compression. Not supported in risr/ assess.