Upon checking the source format of your 3rd image, it turns out that it's not right. Your are giving the entire google search results link instead of the exact image url. The exact image url of the image is ttps://i2-prod.mirror.co.uk/incoming/article8109391.ece/ALTERNATES/s615b/Rooftop-in-Hong-Kong.jpg (I just removed the "h" from https so you can see the code). Image url usually end with .jpg, .jpeg, .png, .gif, .bmp.
You can use this tool to easily do it https://steemitcuration.appspot.com/imageformat .
ohhhh i seeeeee. I didn't know that. Thank you so much for your advice @bayanihan. That's so nice of you. I'll bear that in mind. <3