You can simply skip it as follows:
def to_pillow(examples):
urls = examples['Photo']
images = []
for url in urls:
try:
image = Image.open(requests.get(url, stream=True).raw)
images.append(image)
except:
pass
examples['image'] = images
return examples
dataset = load_dataset("TheNoob3131/mosquito-data")
dataset = dataset.map(to_pillow, batched=True)