Image Files

Choosing file types for images in OCHRE

For photographs, we recommend using JPG as the default image type to view in OCHRE and to call using the OCHRE API.

However, OCHRE supports various other image formats for specific purposes.

  • TIF Images: OCHRE can manage TIF images as an archival format. TIF images can be viewed in OCHRE, however they are not appropriate for viewing on the web. If you wish to manage an archive of TIF images, we recommend also creating JPG images from these TIFs.

  • HEIC Images: Until the high-efficiency image type(s) become more common, we do not recommend using them. Note: many Apple devices use HEIC as the default image type. If you are using an Apple device to produce images to integrate in OCHRE, either change the default format for the Camera app to "Most Compatible" or convert the HEIC images to JPG before importing them into OCHRE. See https://support.apple.com/en-us/HT207022

  • RAW Images: As with TIF images, OCHRE can manage RAW images as an archival format. However, to view images in OCHRE and on the web, convert RAW images to JPGs.

  • PTM/RTI Images: OCHRE supports these file types, but contact the OCHRE Data Service for support using Polynomial Texture Map or Reflectance Transformation Imaging file types.

File size

For photographs and other images, we recommend maintaining the highest possible quality image as an archival file, then creating both a thumbnail and a reasonably-sized large image to view in OCHRE and on the web.

Sure, you could save all your images as 50MP raw files or 250MB TIFs, but for the sake of speed and bandwidth, it is usually prudent to save these as archival files that can be accessed when needed.

As general guidance, consider creating a thumbnail that is 400 x 400 pixels. If you are using a program like Photoshop, consider changing the image quality to Medium, or something like 7 out of 12.

For your large image, consider creating an image that is in the neighborhood of 3000 x 4000 pixels. In this case, the quality can remain high, which is expressed in Photoshop as 12 out of 12.

Special note about images produced from vector files: while these files may be quite small in bytes, we still recommend producing an image that has a dimension of less than 9000 x 9000 pixels.