It's not just dimensions. In fact, it's less about image dimension than image quality. For display on a computer monitor, a JPEG "quality" of "75" or so is more than adequate. The lower the "quality", the more compression and loss of fine detail, but we're not printing them on photographic paper at 1200 dpi, we're viewing them on a monitor at 72 or 96 dpi.
We also don't need embedded thumbnails or color profiles.
Don't most digital cameras and/or the associated software provide for an "email" setting? <i>That</i> would most likely be most appropriate for a venue like this.
See my posts in the "gunning marks" thread.
By the way, I agree that the highly asymmetrical notch is a needless excess of cutting. Not only is there more lineal unit of measurement worth of cutting being done, it's more along the lines of ripping than cross-cutting, thus harder on the gear even when the <i>same</i> length of cut. The only savings is that no upward cuts would generally need be made; we all know those take a bit more effort to accomplish, but I doubt whether avoiding them in the manner described in this thread even comes close to an overall equality of effort.
Glen