Shorten the text to just 'meeting another Magnum owner'. Less text means the thumbnail is less stuffed, and you can make the font bigger.
And make sure the font stands out, you want maximum readability with text on thumbs. I would even use an easier to read font. Also make the colour of the font stand out with contrast, outline, and a drop shadow. Your font is way too small on both pictures. Keep in mind most people are seeing them on tiny phone screens.
And the image itself feels too crowded, the car doesn't really stand out. You tried making it stand out with a red arrow and those blue lines, but they aren't that effective and make the pic seem more crowded. I would cut the car out, and either outline it or blur the background.
A picture says more than a thousand words, so if you could just send me the image without any texts, I could make you a thumbnail tomorrow.