Reference page graphic disappears from published .chm

Hello, all.

I am using FM 2015 in a Win 10 environment.

Here is a detailed explanation of a table format using a paragraph tag that employs "frames" in a wonky way, icons, and the reference page. The explanation leads to this question: why do certain warning icons disappear from my .chm output?

Our documents contain notes, cautions, and warnings. Each has an associated icon:

The Note, Caution, and Warning formats are actually tables:

Each table is a separate table format.

The Note, Caution, and Warning icons are integral to three paragraph formats: zzNote, ZZCaution, and ZZWarning. Each of these paragraph formats employs an icon graphic that is stored on the Reference page. These icons are treated like "frames," even though they are in fact graphics.

As an example, the Warning table uses the zzWarning paragraph format in the left-hand cell. It supplies the hand graphic as a frame. It is called "Warning" and is named "Warning" on the reference page:

On the Reference page, the Warning "frame" is actually this graphic. I typed the word "Warning" underneath the graphic, but the graphic itself is also named "Warning" (if you click on it, you see that name). Here are all three as they appear on the Reference page:

So, the table uses the ZZWarning paragraph format in the left-hand column to populate it with the warning icon:

Whenever I insert a Warning table in a .fm file, the exclamation icon appears in the left-hand cell, and the two rules appear in the right cell. (They are attached to a "WarningText" paragraph format that calls those frames from the Reference page.)

Okaaayyyyyy.

So, when I publish a .chm from the .fm file, I get both columns of the Note, Caution, and Warning tables. In the case of the Warning tables, I get the rules above and below the text, which are also stored on the Reference page. They behave as expected. But the icons disappear.

Why do the icons drop out?

All suggestions gratefully received.

--Nancy