The rare extended radio-loud narrow-line Seyfert 1 galaxy SDSS
  J1030+5516 at high resolution
  Recently, Rakshit et al. (2018) reported the discovery of SDSS
J103024.95$+$551622.7, a radio-loud narrow-line Seyfert 1 galaxy having a $\sim
100$ kpc scale double-lobed radio structure. Here we analyse archival radio
interferometric imaging data taken with the Very Large Array (VLA) at 5 GHz,
and with the Very Long Baseline Array (VLBA) at 4.3 and 7.6 GHz. Two hotspots
and a compact core are detected with the VLA at arcsec scale, while a single
milliarcsec-scale compact radio core is seen with the highest resolution VLBA
observations. The Fermi Large Area Telescope did not detect $\gamma$-ray
emission at the position of this source. In the mid-infrared, the Wide-field
Infrared Survey Explorer satellite light curve, covering more than 7 years and
including the most recent data points, hints on flux density variability at 3.4
$\mu$m. Our findings support the notion that this source is a young version of
Fanaroff-Riley type II radio galaxies.
