Breadth-first quad encoding is shown to be a good method of picture representation for networked browsing of colour raster pictures. The twin requirements of partial transmission and compression are discussed. Efficient algorithms for the display of sub-areas of a picture, at varying resolution, are developed; suggestions are made for further generalisation. Particular attention is paid to tesseral addressing, and the way that it can be exploited to produce efficient traversal and display algorithms. A sample non-recursive algorithm is included. The problem of quad-encoding arbitrarily dimensioned pictures is addressed.