When you upload images to Tailwind for scheduling to Pinterest, we take your image and save the original, full resolution and uncompressed image on our servers to send directly to Pinterest when that Pin gets published. We do create optimized versions at different resolutions to show as thumbnails and at different sizes around the Tailwind dashboard but we do not send these to Pinterest.
When it comes time to send your Pin to Pinterest, we send the raw image you uploaded as-is. Pinterest automatically processes and applies their own compression to every image published on the site.
For instance, they will resize any image wider than 735px to fit that width, so if you're images are wider than that they're going to be resized to that width while maintaining the same aspect ratio. We recommend uploading images already at that maximum width for Pinterest as they will just be resized anyway. Outside of that, any image artifacts you notice when the final Pin is published to Pinterest will be from the optimizations they apply to all images on the site.
There are a few things you can do to make sure your Pins still look great after Pinterest optimizes them:
Upload your images at a minimum width of 600 pixels and a maximum width of 735 pixels
Keep your images at Pinterest's preferred aspect ratio of 2:3 or 1:2.8
Make sure your text is easy to read, in a large enough font and in a color that stands out from the background.
Consider how your image will look on a smaller screen, as most Pinterest usage happens on mobile devices
Read more about making your Pins look great in our blog post: How to Create Beautiful Pinterest Pins