It is shown that the resolution in microsphere-based imaging is enhanced with decreasing the period of nanoplasmonic arrays used for structured illumination of nanoscale objects represented by dye-doped fluorescent nanospheres. It is demonstrated that the maximal resolution about λ/6-λ/7, where λ is the operation wavelength, is possible without post-imaging processing. It is shown that achieving the maximal resolution requires the coupling of the nanosphere emission to the localized surface plasmon resonances in the periodic arrays.