to answer the photo question, not the pen question

I use Fast Stone Photo Resizer.  Free. Works well.

http://www.faststone...sizerDetail.htm

OK - so this is a correct and interesting unusual Parker item.  I am still a little perplexed by what looks to me like different chasing on the cap and barrel. But that is not really important to the discussion of the clip.

Now that I have a name for the clip, I have some "quick and dirty" Google results

There is a patent date on the clip in one item on ebay in the past

  I just started looking at that patent date and found some cute things for clipping pens to pencils, but not for this clip yet.

That is really interesting and totally new info to me!  Thanks for finding the answer and thanks for sharing it.   

So I guess when you post the pen, it somehow pushes the clip into the barrel?

I am not the definitive expert. However, the crack at the top of the clip usually indicates that the original clip was broken off.  The current clip (in my opinion) has a homemade appearance to it.

There are Parker pens with VV clips, but those have a transverse pin to hold them, and this does not appear to have that type of hole.  Then again, I am not familiar with a long slit like this for any type of clip that I can think of. So that cut in the cap is a bit of a mystery to me.

Furthermore, the chasing pattern of the cap does not match the barrel.  In my opinion that cap is old, and a good fit, but not original.

The earlier Swan lever filling pens, of which this is an example,  are from the early 1920s.  This might even have "SF2" stamped on it somewhere.  There do not seem to be further detailed model numbers.  Some were stamped "posting" on the barrel, or like this one, "stenograph" to indicate the original nib type. Most had no such notation.

Could you please post a picture of the lever as well?

Assuming it has a rather standard looking lever, the pen is from 1920 through the mid 1920's.  The arrows and message about the screw cap makes it on the earlier side of that date range.  Swan introduced lever filling pens about 1919, and the first year they used a split lever that looks like a broken lever to most people who have not seen it before. They quickly moved on to a standard lever about 1920.