Nice hint töday!
Of course, it would have been even easier if somebody didn't tipped on the attachments button method
Now we are back to the dumb full-length scrolling of all adequately hinted at post!

Next I suggest you embed the letter image at the end of a gif animation, with the letter flashing only a fraction of a second!
Or you can replace the image by some ascii art
........................................
...................=8...................
..................7++,..................
.................=77~+..................
.................+=7?I7.................
................D+?7+I~:................
................~$DI7~~I................
...............D?I7+Z7O$Z...............
............,I$~+=~II$$+7$,.............
.O$IIIO$$II7?I+I$$$$$$$$$?O7~+?~??$?$$,.
.,I??IO?I+$??O$Z$$$$$$$ZZZ7$7$?I?OO7I...
..,.7++$+$$7+77?$+Z$$Z7IZ+I=+I~??Z+7,...
......?7$Z~?7:++$+$$$$~?7?Z=+II$=?,,....
.......,I7Z=:I7:I7$$$$~+II?Z7IZO........
.........,+$?IZ+IO$$$$=O+Z777O..........
..........I?ZZ77$I$$$$+7O?O+D...........
..........$=7I++=7Z$$7?Z?Z+7Z...........
..........+++++Z7+$$$$~=I???~...........
.........+=~I=I?I7??+~77I$$+IO..........
.........Z?I+7=++7...I~Z=?Z$=7..........
.........I=$???7.......++7+7=?~.........
........7II=+,..........,.?=$?O.........
........+I7,................$?$,........
........~.....................I.........
....................