Have you ever noticed your email been cut off in Gmail, this is because of the Email file size is larger than 102kb. A quick fix i found for this was to get rid of unwanted spaces in your HTML by using this tool https://htmlcompressor.com/compressor this helps in stripping and optimising the file size to the barest minimum.

Please note: the 102kb limit is based on the amount of content in the HTML code, not the size of specific images in your message. While resizing an image will not change the size of the content, deleting an image from the email body will reduce the size of the message.