Cat owners - is she too thin?

[countdowntonap]

A neighbour gave their cat to another neighbour about two months ago. Recently, her appearance has changed significantly and she’s lost a lot of weight. I’ve never owned a cat, so not sure what she should look like, but her hips are protruding a lot. Please can you let me know if this looks normal?
She ran into our house this morning and I was shocked at how different she looked.

Looks fine to me. Can you get a top down shot of her while she's standing?

If the people who have been looking after her haven't intentionally tried to get her to lose weight then I'd think she needs to be checked.

Yeah looks fine to me.
My cat is about the same size. She’s always been petite and never had any concerns from vets etc about her size.

How old is she? They get like that as they get old

A standing shot would be better

I have one cat who is very thin, but is healthy. The vet said it was just normal for her. My other cat is much stockier - both eat same amount of food and are watched to check they don't eat each others.

Was she tubby before? Was she hassling you for food?.

If she's lost a load of weight recently then she needs to be taken for a blood test, 2 of my cats have died young from hyperthyroidism and kidney disease and it needs to be caught early.
Current cat had severe uncontrolled hyperthyroidism and I took this one to have radioactive iodine covered by her insurance, it was amaxing, she is completely cured and looks great, she's back to her normal weight although it has left her with a heart murmur.
She's made it to 19 with good treatment.

Could she just have lost her winter coat?