Feature request: Support image metadata in embedding visualizer

[acganesh]

I'd like to use TensorBoard to visualize an embedding for training data. I have ~100K images, that are 1000x1000. The images are too large for the sprite thumbnails -- as per the docs, it appears that the sprite loader supports a total resolution of 8192 x 8192.

Is there a way I could attach my images to the metadata card?

While the existing metadata.tsv parser only supports text data, it seems like I could achieve this functionality by editing the HTML here. It would be nice to have a more elegant solution -- perhaps by linking metadata to existing TensorBoard image summary visualizations.

Any suggestions / comments are appreciated, thanks.