Your code seems to be correct for loading an image and setting it as the bitmap for your button button. As Rick stated, first check if the path you use is correct and if it is returning something,
Add error handling and debugging statements to your code to check if your 'Load' and 'Attach' functions are returning any error codes -
HRESULT hr = image.Load(str_path);
if (FAILED(hr))
{
CString errorMessage;
image.GetLastErrorDescription(errorMessage);
AfxMessageBox(errorMessage);
}
if (!bitmap.Attach(image.Detach()))
{
AfxMessageBox(_T("Failed to attach the bitmap."));
}