One thing that has always intrigued me about any of Dickinson's work is her use of punctuation, you just don't see it anywhere else, and it changes the meaning of the work so much. Especially in this poem. Just from the words of it, it could be taken as the narrator being someone who is so lonely and suddenly the narrator finds someone sharing their trouble and is overjoyed by it, but doesn't want to ruin the moment by shouting it out to the world. However, once you throw in Dickinson's ever clever, and for her time innovative, use of dashes to signify pauses, the poem, to my ear anyhow, reeks of sarcasm.
For instance, take the very beginning. In the first line, "I'm Nobody! Who are you?", Dickinson makes the narrator almost sounds like one of those overly innocent schoolgirls that we all used to know. But with the second and third line, "Are you -- Nobody -- too?; Then there's a pair of us!" the nobody just makes it sound too much like a mocking of the reader. Either Dickinson was irate when she was writing this, or I am seeing the "truth" that she is telling me in a different sort of "slant" (and that was probably a very poorly worded reference to another poem of hers). Regardless, the nobody jumps out at me as being the tone-setter, so to speak, for the rest of the poem.
Then there is the next line "Don't tell! they'd advertise -- you know!", by that time, is just insinuating too much of something to not be either sarcastic or mocking...or at least childish and playful. What is the proverbial "you know" that the speaker speaks of? I'm sure only Emily knows for sure, but I'll take a wile stab at it and say that she means that two nobodies met and suddenly they both feel like they're somebody, something that I feel the narrator doesn't want.
The second stanza seemed a little hazy to me until I looked at it in full light (or for use who speak normal English, at all four lines of the stanza). Once again the stanza isn't as much of a break of thought for Dickinson as it is a matter of habit, because you could just as easily throw both of the stanzas together and the poem would be just as complete. The first line being "How dreary -- to be -- Somebody!". The "to be" being separated in my mind has more to do with the difference between being nobody and being somebody...so I guess the two stanzas are a transition between the two. Still, this could survive as one stanza.
What images did this poem evoke...not too many really outside of what I've mentioned above. The Frog and the Bog symbols went right over my head, and I'm still scratching it trying to figure the right words to put the context in. Something along the lines of someone being so used to something that though others may think it's ugly, they've found it to be beautiful in some way shape or form...but that's just taken out of context...but it still works. I believe that this poem is nothing more than a mockery. It mocks the common held thought (especially in the Romanticism that was abound in her time) that two people could meet and fall in love at first sight. She isn't directly mocking the actual falling in love, but she's mocking the idea underlying it. Then again, that's just my opinion, I could be wrong.