There is a setting to allow you to not scale down images when sharing:
An important note on this setting, is that if you capture on a retina monitor (Mac laptops), the image will appear quite large to anyone you share with who isn't viewing on a retina display. That is, besides drag and drop, if you use the share menu, the full quality image will be shared and appear "normally" to you, but larger than "normal" on the receiving end.
Hopefully this helps out! Please let us know if you have any questions.