I use a javascript image processing library to manipulate an image, and when I'm done I want to have the possibility to save the image (a new file) to the server and keep track of it in a database. The database part is no problem, but how do I save the image without losing the manipulation done?
Are there any libraries for that or is it easiest to just do it myself?
It doesn't seem like Pixastic provides an interface for this, specifically, but there is a property in the options giving you the resulting canvas:
var options = {};
Pixastic.process(image, "action", options);
options.resultCanvas; // <- holds new canvas
This canvas object you can use to obtain a "data URL":
options.resultCanvas.toDataURL('image/jpeg')
Uploading 'canvas' image data to the server
The "data URL" is a tiny header (see the so-post linked) and the file content in a string. You can post this to the server for storage.