picture tag source issue

[shldhee]

왜 wepb가 없으면 jpg가 보여줘야되는데 안될까?

<picture>
                  <source
                    media="(max-width: 1275px)"
                    :srcset="item.mobile_banner_image.replace('.jpg', '.webp')"
                    type="image/webp"
                  />
                  <source
                    media="(max-width: 1275px)"
                    :srcset="item.mobile_banner_image"
                    type="image/jpg"
                  />
                  <source
                    media="(min-width: 1276px)"
                    :srcset="item.pc_banner_image.replace('.jpg', '.webp')"
                    type="image/webp"
                  />
                  <source
                    media="(min-width: 1276px)"
                    :srcset="item.pc_banner_image"
                    type="image/jpg"
                  />
                  <img
                    :data-index="index"
                    class="banner-view__image"
                    :src="item.pc_banner_image"
                    :alt="item.alt_text"
                  />
                </picture>