Whenever I want to post photo on Instagram?

OK, so I have a phone and I want to upload a photo on Instagram, but my phone says "Your SD card is full". I don't even have any pictures on my phone except the one that I want to upload which means only one picture. But I do have 100+ music. I don't think music is the problem. My SD card is 6 GB. My phone type is Lenovo A680.

Go to settings, and turn OFF "save original photos". That will fix the problem.

Turn off saving files. Your SD card space shouldn't matter when uploading, since you're not putting anything on it.