Harman, 27, was found guilty late Monday on six of the seven charges she faced for her role in the mistreatment of Iraqi inmates in late 2003.
A hearing to determine her sentence was set to begin Tuesday morning. She faces up to 5½ years in prison.
The jury of four Army officers and four senior enlisted soldiers deliberated for less than four hours before convicting Harman on one count of conspiracy to maltreat detainees, four counts of maltreating detainees and one count of dereliction of duty.
She was acquitted of allegedly photographing a group of Iraqi prisoners forced to masturbate in public by Abu Ghraib guards. One of Harman's co-defendants testified last week that she was not present when that incident occurred.
The Army reservist showed no reaction when the verdicts were read. She left the Fort Hood courthouse without speaking to reporters.
Harman, a former pizza shop manager from Lorton, Virginia, appeared in several of the most notorious photos taken at Abu Ghraib, and she was found guilty of taking other pictures.
The photos showed prisoners chained together in sexual poses, piled on the floor naked and forced to form a nude human pyramid.
In one picture, Harman posed with Graner behind a group of naked detainees. In another, she was shown with a prisoner on whose leg she is accused of writing "rapeist."
In closing arguments Monday, prosecutors said Harman and other guards conspired to physically hurt and sexually humiliate the prisoners under their watch.