The imageresolution is the level of detail of an image and a measurement of image quality. Higher resolution means more image detail, for example when two structures 1 mm apart are distinguishable in an image, this picture has a higher resolution than an image where they are not to distinguish.
More data points in an MR image (with same FOV) will decrease the pixel size, but not accurately improve the resolution because the different MRIsequences influence the contrast and the discernment of different tissues.
With high contrast and optimal signal to noise ratio, the imageresolution is depend on FOV and number of data points of a picture, but T2* effects have an additional influence.