I have added an image field with Translatable Content enabled. My content type has enabled translations too. But when I add an image in the translation, the english contents field get replaced with the newly added translated image. (English is my base language, and I have Japanese and Chinese as translations). This happens vise versa too. What could be the issue?
By default only the image alt and title are translatable and the file itself isn't. By the default the file is always the same in all languages. You can simply make the file to be translatable as well under https://example.com/admin/config/regional/content-language.
Note: After you've done this, all your existing translations will need to have the file re-uploaded (or a new file uploaded), as the default only gets added once when translating content through the UI.
Taken the above Hero image field this can be done manually be editing
field.field.node.page.field_hero_image.yml (which translates to
Before file checked:
third_party_settings: content_translation: translation_sync: alt: alt title: title file: '0'
After file checked (alt and title are mandatory if file is checked, that's why they have
third_party_settings: content_translation: translation_sync: file: file alt: '0' title: '0'