Can you share the whole code you are trying to use?
For me this works (yeah its colors instead of images):
Code:
QString buttonStyle(
"QPushButton {color: rgb(255,0,0);\n"
"background-color: rgb(0, 255, 0);\n"
"border-bottom: 1px solid rgb(33,33,33);\n"
"border-right: 1px solid rgb(33,33,33);\n"
"border-top: 1px solid rgb(220,220,220);\n"
"border-left: 1px solid rgb(220,220,220);\n"
"border-radius: 3px;\n"
"font-weight: normal;\n"
"font-size: 16px; } \n"
"QPushButton:pressed {background-color: rgb(75, 75, 75);\n"
"border-top: 1px solid rgb(33,33,33);\n"
"border-left: 1px solid rgb(33,33,33);\n"
"border-bottom: 1px solid rgb(220,220,220);\n"
"border-right: 1px solid rgb(220,220,220); }\n");
QPushButton *testBtn = new QPushButton("Click me", this);
testBtn->resize(QSize(100, 30));
testBtn->setStyleSheet(buttonStyle);