We have obtained 850 and 450 km continuum maps of 21 low-mass cores with SEDs ranging from pre-protostellar to Class I (18 K), using SCUBA at the JCMT. In this paper we present K \ T bol \ 370 the maps, radial intensity proÐles, and photometry. Pre-protostellar cores do not have power-law intensity proÐles, whereas the intensity proÐles of Class 0 and Class I sources can be Ðtted with power laws over a large range of radii. A substantial number of sources have companion sources within a few arcminutes (two out of Ðve pre-protostellar cores, nine out of 16 Class 0/I sources). The mean separation between sources is 10,800 AU. The median separation is 18,000 AU including sources without companions as a lower limit. The mean value of the spectral index between 450 and 850 km is 2.8^0.4, with pre-protostellar cores having slightly lower spectral indices (2.5^0.4). The mean mass of the sample, based on the dust emission in a 120A aperture, is 1.1^0.9For the sources Ðtted by power-law M _ . intensity distributions the mean value of m is 1.52^0.45 for Class 0 and I sources, at 850 km and 1.44^0.25 at 450 km. Based on a simple analysis, assuming the emission is in the Rayleigh-Jeans limit and that these values of m translate into power-law density distribu-T d (r) P r~0.4, tions (n P r~p) with p D 2.1. However, we show that this result may be changed by more careful consideration of e †ects such as beam size and shape, Ðnite outer radii, more realistic and failure of the T d (r), Rayleigh-Jeans approximation.