As my intentions are good and I don't want to be misunderstood; here is my conclusion above my principal reasoning.
Middle Voice is always "MiðMynd"
but on the other hand
"Miðmynd" is not always Middle voice that is when it's not reflexive.
Incongruity between the English definition "Middle Voice" and The Icelandic definition
of "Miðmynd" is obvious conclusion driven from the underlying examples.
I recommend those not wanting to sound like newbie to avoid using the term "Middle Voice" to substitute the Icelandic spelling "MiðMynd". Use instead separately depending of the case terms like "reflexive" and "passive".
"Passive Middle Voice" is even more confusing to be of usage.
Common plain Definition (Babylon.com) (I like it)
Middle Voice (gram.) that form of the verb by which its subject is represented as both the agent, or doer, and the object of the action, that is, as performing some act to or upon himself, or for his own advantage...
Rendered into Icelandic current spelling just below:
"Middle Voice" er sú mynd sagnarinnar þar sem frumlagið er sett fram sem bæði gerandinn og þolandi gerðarinnar, það er, sem gerir eitthvað gagnvart sjálfum sér eða við sig sjálfan eða í sína eigin þágu.
Another common plain Definition (Babylon.com) [I love it]
n: the voice used to indicate that the grammatical subject of the verb is the recipient (not the source) of the action denoted by the verb.
Another rendered into Icelandic current spelling just below:
kv.: Sú mynd sem gefur til kynna að frumlag sagnarinnar sé andlag [/þolandinn] (ekki uppspretta) gerðarinnar sem sögnin markar.
[I know this is unbelievable but I'm not responsible or its publication.]
Now you will see 2 extracts from major common official native dictionaries.
I have done my best in rendering the text into English words.
Sigfús Blöndal: ÍSLENSK-DÖNSK ORÐABÓK 1920-1924.
miðMynd f.(gramm.) MedialForm [Middle Voice?], ReflexivForm [Reflexive Voice?], mediopassiv Form [Middle passive Voice?].
Menningasjóður: ÍSLENSK ORÐABÓK 1963.
MiðMynd kv, beyingarmynd sagna, sem í [rithætti] nútíma íslenzku endar á st og sýnir, að inntak sagarinnar kemur fram við frumlagið sjálft (t.d. "klæðast" = klæða sig, einnig gagnvirkt um frumlagið, "þeir hittust" = þeir hittu hver (hvor) annan);
hefur stundum þolmyndunarmerkingu (t. d. "ég sást" = var séður);
miðmyndunarsögn sögn, sem aðeins er til í miðmynd (t.d. "ferðast, nálgast").
"Miðmynd" f, verbal Voice form, by which in current Icelandic [orthography] the verbs take the suffix -st and shows, that the intake of the verb [the suffix] appears near the self subject (e.g. "get dressed" = dress one self, also reciprocal concerning the subject, "they met" = they hit each other);
has sometimes passive meaning [e.g. "I was seen" = was cunning);
Verb of "Miðmynd" verb, which just exist in "miðmynd" (e.g. "traveling, approaching");
Middle Voice is always "MiðMynd" but on the other hand
"Miðmynd# is not always Middle Voice that is when it's not reflexive.
Uoden the ON-Amateur.
Refurinn var séður í fjallinu, hann sást ekki drepa lambið.
The fox was cunning in the mountain; it was not seen kill the Lamb.
Til allrar óhamingju, sást til gjaldkerans, hann var ekki séður.
Unfortunately, the cashier was seen, he was not cunning.
Þeir hittust, þar hinir voru í snjókasti; það er að hitta hverja aðra, með snjóboltum.
They met, there the others were in snowballing; that is hit each other, with snowballs.
Ég klæðist vegna veðráttu, siðferðis og í tímaþröng, ég klæði mig í makindum.
I get dressed out of clima, ethics and in urgency, I dress myself in leisure.
cið>cð=sjeö=sèð=séð for sure [the c]. Ic or k ? k er ist ? St er ik>Sterk or Styrk.
cunnig'ur or kunnulegur. I see: c.