If your email exceeds 102K, Gmail will display the first 102K and then it will clip off the remainder with a few different variations depending on the device.
In the web version, Gmail will display a message that reads:
[Message clipped] View entire message
Clicking on the link will open your email in a new window.
In the mobile version of Gmail for the Android - your email will just get cut off with the proverbial "..." Unfortunately there is no link for viewing the entire message.
In the mobile version of Gmail for the iPhone, you will see a message at the bottom of your email stating:
[Message clipped] Download entire message
After clicking on that link, it will re-open the email but you'll have to scroll all the way back down to place were you left off. Even after scrolling all the way back down to the bottom, my test email was not displayed in it's entirety. Instead it was left with more dots "..." and no link to view more.
The mobile version of Gmail for the iPad does not appear to offer any links for viewing the entire message, instead the email is simply cut off.
In my initial testing, my HTML document did not contain any images, it consisted of mostly text with very little HTML coding. I also tried this test with embedded images and concluded that since the images are not considered part of the original HTML content itself, they were not clipped nor did they effect the message of my email. Instead, they were downloaded as one might expect after clicking on the "Show Images" link.
So what's the fix?
If you are close to 102K, you might save a few bytes by removing any unnecessary spaces, carriage returns or comments.