Blurred pictures on iPhone XS Max?

Since yesterday I own an IPhone XS Max. I'm from Android, so I'm an Apple novice. Yesterday I wanted to transfer my photos of my Huawei to the iPhone (in different ways) but in the end I only succeeded in manually loading the photos of the Huawei on the laptop and then via iCloud on the iPhone. But that took forever, so I stopped it and only a fraction of it loaded from what I would like… The iCloud memory is now occupied by 1.5GB of 5

Now to my real problem: When I was traveling on Instagram and today via WhatsApp a picture and text was sent, I noticed that it is slightly out of focus… The original I have seen in parallel on another phone, where it was sharp,

I have already looked a bit on the Internet and in the photo settings "memory optimization" identified, but the photos are still slightly out of focus. I have now synonymous made the iCloud because I'll have the photos anyway only on my iPhone and nowhere else.

I have 256GB memory and they are just 15GB occupied. Every now and then I have already turned on the iPhone.

Why are the photos on Instagram / Facebook slightly out of focus?

Why the ones I get at WhatsApp?

A friend who has a 8, the photo also has sharp on his phone.

Would be great if you can help me:-)

I can only give you an answer to WhatsApp here. There images are not sent at full resolution. When you send a picture with WhatsApp, the resolution of each device is automatically reduced. Therefore: Send reminder photos etc. Never about WhatsApp.

Thanks, that was almost clear to me… But the friend was also keen on WhatsApp.

I never did that experience. Unfortunately I can't help then 😅