The camera's preview
Every RAW file holds a JPEG preview that the camera made when you took the photo. Many cameras save this preview at the full resolution of the photo, or very close to it.
When the camera's preview is full size, LightGPX shows it directly. The photo looks the way your camera made it and opens without a wait. LightGPX saves only small copies of the preview for thumbnails, so these photos take little space on your Mac.
LightGPX's own render
Some cameras save a preview that is much smaller than the photo. Many Sony and Panasonic cameras, DJI drones, and Fujifilm cameras older than the X-T3 generation do this.
For these photos, LightGPX renders the RAW at full resolution once and saves the result on your Mac. LightGPX does this in the background when you create an album. The album opens right away and shows the camera's previews first. Each photo switches to the full-resolution render when the render is ready. A photo you open is rendered before the others.
LightGPX renders these photos so that zooming in to 100% shows the real detail of the photo. LightGPX never enlarges a small preview and presents it as full size.
Which photos get which
| Photo | What LightGPX shows |
|---|---|
| RAW with a full-size camera preview | The camera's preview, at full resolution. LightGPX saves no extra full-size copy. |
| RAW with a smaller camera preview | LightGPX's own render of the RAW, at full resolution. LightGPX saves the render on your Mac. |
| RAW that LightGPX cannot render | The camera's preview, marked Embedded Preview. Full-resolution detail is not available for this photo. |
| RAW with no preview that LightGPX cannot render | A placeholder that says Unsupported format. |
| JPEG, HEIC and TIFF | The photo itself. These formats need no render. |
| Photoshop documents (PSD, PSB) | The flattened image that Photoshop saves inside the document. A document saved with Maximize Compatibility turned off holds no flattened image, so LightGPX shows Unsupported format. |
Very large photos
LightGPX opens photos longer than 16,384 pixels, such as stitched panoramas, in pieces. You can zoom and pan them smoothly, and LightGPX loads the part you look at.
Edits from other apps
Previews show the photo as the camera captured it. They do not show edits you made in Lightroom Classic or in other editors.
Space on your Mac
LightGPX keeps previews for every photo in your library so browsing stays fast. Settings > Storage shows how much space they take, in four rows.
| Row | What it holds |
|---|---|
| Full size | LightGPX's full-resolution renders of RAWs whose camera preview is smaller than the photo. This row is empty when all your RAWs have a full-size camera preview. Large photos such as panoramas take the most space. |
| Large previews | Previews of JPEG, HEIC and TIFF photos and of rendered RAWs, sized for full-screen viewing on your display. |
| Small previews | Small copies of JPEG, HEIC and TIFF photos and of rendered RAWs, for grid thumbnails and map pins. |
| Camera previews | Small copies of the camera's own preview. LightGPX shows these first, while an album is still rendering. |
Discard Full Size Previews in the same window frees the space of the Full size row. LightGPX renders those photos again in the background, and right away for a photo you open.
When you remove a photo or an album, LightGPX removes its previews too.