  We present an International LOFAR Telescope sub-arcsecond resolution image of
the nearby galaxy M 51 with a beam size of 0.436" x 0.366" and rms of 46
$\mu$Jy. We compare this image with an European VLBI Network study of M 51, and
discuss the supernovae in this galaxy, which have not yet been probed at these
low radio frequencies. We find a flux density of 0.97 mJy for SN 2011dh in the
ILT image, which is about five times smaller than the flux density reported by
the LOFAR Twometre Sky Survey at 6" resolution using the same dataset without
the international stations. This difference makes evident the need for LOFAR
international baselines to reliably obtain flux density measurements of compact
objects in nearby galaxies. Our LOFAR flux density measurement of SN 2011dh
directly translates into fitting the radio light curves for the supernova and
constraining massloss rates of progenitor star. We do not detect two other
supernovae in the same galaxy, SN 1994I and SN 2005cs, and our observations
place limits on the evolution of both supernovae at radio wavelengths. We also
discuss the radio emission from the centre of M 51, in which we detect the
Active Galactic Nucleus and other parts of the nuclear emission in the galaxy,
and a possible detection of Component N. We discuss a few other sources,
including the detection of a High mass X-ray Binary not detected by LoTSS, but
with a flux density in the ILT image that matches well with higher frequency
catalogues.
