I have created an application that will upload the users images to the blobstore, then perform some transformations on them. I need to save this new image to the blobstore. So far, I have resorted to using datastore blob types, however these have a maximum file size of 1MB.
Is there a way to programatically upload files to the blobstore without having to use a form and a POST event handler?
There is, but it is deprecated.
Instead, as that doc says, you should write to Google Cloud Storage - you can still use the Blobstore to serve the files from there.