Option to initialize image with arbitrary other image

[qwertystop]

Main hypothesized use: Batch jobs of individual frames of animation, priming each frame with the prior frame's output for increased consistency across time. Appears to be effective for that purpose. I have not yet tested initializing with irrelevant other images, as I'm currently processing the animation I made this change for.

This is the first pull request I've done - apologies if I've missed something. Also first time I've touched lua, but this was a simple addition.

[pieterjongsma]

@qwertystop How were your results? Could you show some comparison?

[qwertystop]

Well, I do not currently have either the original attempt without my modification, or the hardware I ran it on (got an upgrade), but here's the animation I made with it:

The source animation was here, and for style I used a random image of lightning off Google - can't recall which.

Probably needs more testing; I admit it kind of skipped my mind once I had the initial animation done. I'll find some gifs and a more interesting style, try to find time to test more this weekend.

[qwertystop]

That... Huh. Guess I can't embed images here? At least, it's invisible for me. Here's a link.

[pieterjongsma]

Thanks for your swift reply! I expected those files might have been lost. I was curious whether this would interfere with the content of the image, but from your example that doesn't seem to be any issue. Great!

[crowsonkb]

This is a useful option for a number of reasons - in addition to what's mentioned, it can also be used to increase the image quality at high resolutions by rendering at a lower resolution first then initializing the render with a scaled-up version of the low-res render. There are a number of people's high-resolution scripts that would probably benefit from such an option.

[qwertystop]

@crowsonkb Do you have any examples? I haven't really tried any non-default-resolution style transfers.

[ProGamerGov]

@qwertystop It seems this feature was added to Neural-Style on December 6th: 197ad42

[qwertystop]

Fair enough. A cleaner version of my change, since I'd never actually touched Lua when I made this PR. I'm not certain how it would be resolved, since the change has the same content? Don't want to just leave this hanging as though the feature was dropped, though.