Is it good practice to use std::vector as a simple buffer?

Question

I have an application that is performing some processing on some images.

Given that I know the width/height/format etc. (I do), and thinking just about defining a buffer

Answer 1

Besides what other answers mention, I would recommend you to use std::vector::assign rather than std::vector::resize and memcpy:

void MyClass::OnImageReceived(unsigned char *pPixels, unsigned int uPixelCount)
{
    m_pImageBuffer.assign(pPixels, pPixels + uPixelCount);
}

That will resize if necessary, and you would be avoiding the unnecessary 0 initialization of the buffer caused by std::vector::resize.