Distribution of the ratio of the size of the Hα emission to the size as measured from the F475W filter (top panels) and from the F110W filter (bottom panels). Left and central panels show the sizes in the two directions separately; right panels show the mean size. Vertical solid and dotted lines represent the means with errors. Both in clusters and in the field mean values are larger than 1, suggesting the inside-out growth, but when using the F475W, tracer of the recent star formation, in clusters mean values are even larger, pointing to cluster-specific processes at work.