What is an .ora file?
OpenRaster is an open file format for layered images. A .ora file is a ZIP archive: one PNG for each layer, a short XML file that lists them in order with their names, opacity, visibility and position, and a flattened copy of the whole picture for anything that just wants to show it.
No company owns it. That is the point: it is the format to reach for when a layered image has to leave one editor and arrive in another with its layers still apart. A flattened PNG or JPEG can’t do that.
What’s inside
Rename any .ora to .zip and you can open it. The one rule that trips people up: mimetype has to be the first file in the archive, stored without compression, or some editors refuse it.
mimetype image/openraster — first, stored stack.xml the layer list, top layer first data/layer0.png one PNG per layer data/layer1.png data/layer2.png mergedimage.png the whole picture, flattened Thumbnails/thumbnail.png ≤ 256 px preview
<image w="1920" h="1080" version="0.0.3">
<stack>
<layer name="Logo" src="data/layer1.png"
opacity="0.8" visibility="visible"/>
<layer name="Background" src="data/layer0.png"
opacity="1.0" visibility="visible"/>
</stack>
</image>Export a .ora from Image Horse
- 1Open Settings → Import / Export. It sits beside the other export formats in the top bar.
- 2Press Export as .ora. Every layer is written out as a PNG by the engine’s own encoder, alongside the flattened picture and a thumbnail.
- 3Open it in Krita or GIMP. The file takes your photo’s name. Text and shapes arrive painted into their layers.
Import one back
Import .ora, on the same tab, opens the file as a new photo in your gallery. It never replaces the one you are working on. Image Horse checks the mimetype and the layer list, decodes each PNG with the same Rust decoder that wrote it, and rebuilds the stack with names, opacity, visibility and the active layer intact.
Like everything else in the editor, both directions run on your machine. The viewer at the top of this page does the same thing, without the editing.
What survives a round trip
| In your project | Out and back |
|---|---|
| Layer order, names, opacity, visibility | ✓ Kept, both ways |
| The layer you had selected | ✓ Restored on import; otherwise the top layer |
| Text and shapes | Painted into their layer on export. They come back as pixels, not editable objects. |
| Layer masks | Not written yet. It’s on the list. |
| Layers from another app that are offset or smaller than the canvas | Import places every layer at the top-left, full size, so these may come in blank. The viewer above shows where they should sit. |
| Layer groups and blend modes from another app | Image Horse has no layer groups yet, and imports every layer as normal blending. |
Where else a .ora opens
- KritaOpens and saves .ora directly. The usual next stop for painting.
- GIMPOpens .ora and exports it back. Also the easy way to turn one into a PSD.
- MyPaintUses .ora as its own save format.
Questions
Is my .ora file uploaded when I open it on this page?
No. The archive is unzipped and drawn by this browser tab. Nothing is sent to a server, and the viewer keeps working with the network switched off.
Why is a .ora bigger than a PNG of the same picture?
It holds one full PNG per layer, plus a flattened copy of the whole picture and a small thumbnail. Five layers is roughly six PNGs.
Can I still edit my text after a round trip?
Not as text. Image Horse bakes text and shapes into their layer's pixels on export, so they come back as paint.
Does Photoshop open .ora files?
Not natively. Open the .ora in Krita or GIMP and save it as a PSD from there; the layers carry across.
Is .ora the same as Krita's .kra?
No. Both are ZIP archives, but .kra carries Krita-specific data. .ora is the shared format that any editor can read.