All files are converted to png format and are resized.

Problem/Motivation

All images are converted to PNG format and resized to "Image size limit" set at the settings form.
Such behaviour is confusing a little bit.
I guess images should be downloaded in original format, not sized up to "Image size limit".

Steps to reproduce

1. Install module and configure Acquia DAM module.
2. Configure node to have a field where we can chose images for Acquia DAM.
3. Add a new image to this field with any extension except png.
4. Check that the image was converted to PNG format.
5. At /admin/config/media/acquiadam set Image size limit to 2048px
6. Add a new image from Acquia DAM with width and height less than 2048px
7. Check that image was sized up and its height or width is 2048 px.
8. As a result of such conversions image size in MB is increased in comparison to the original one.

Proposed resolution

I propose:

1. adding an ability to configure whether we want to load original images or set "Image size limit" as it is now.
2. adding configuration whether we allow to size images up if "Image size limit" is set not to "Original"

User interface changes

At /admin/config/media/acquiadam Acquia DAM configuration page in "Image size limit" is added an "Original" option.
At /admin/config/media/acquiadam Acquia DAM configuration page an "Allow size up" checkbox is added after "Image size limit" dropdown.
"Allow size up" checkbox depends on the value of "Image size limit" and is show only if "Image size limit" is not "Original"