# YTThumbFetcher: extended source map Last material review: 2026-08-26 Canonical origin: https://get-youtube-thumbnail.site/ Publisher: YTThumbFetcher Editorial Team Editorial contact: hello@get-youtube-thumbnail.site ## What this publisher can establish YTThumbFetcher can document its own URL parsing, fixed-host thumbnail proxy, caching, AI input boundary, six-dimension visual rubric, task retention, rate limiting, and original editorial examples. It can make evidence-based observations about visible thumbnail composition. ## What this publisher cannot establish The site cannot infer private YouTube Studio impressions, CTR, retention, revenue, traffic sources, or audience demographics from a public URL. It does not claim that a visual level predicts views, recommendation ranking, virality, or revenue. YouTube platform rules and API definitions should be verified against Google/YouTube primary documentation. ## 2026 source note YouTube Help currently recommends 3840 x 2160 upload sources for standard videos and 2160 x 3840 for Shorts. Public thumbnail derivatives may still be 1280 x 720 or smaller. Primary source: https://support.google.com/youtube/answer/72431?hl=en (checked 2026-08-26). ## Data provenance - YouTube Data API: public title, channel attribution, publication time, duration, thumbnail resources, and visible statistics when available. - YTThumbFetcher: visual levels, findings, radar chart, edit suggestions, guides, and original fictional illustrations. - User-requested third-party images: rights remain with the original owner; technical access is not a reuse license. ## Content inventory ### https://get-youtube-thumbnail.site/ Interactive downloader plus evidence-based creator reference. URL input supports watch, Shorts, Live, Embed, and youtu.be forms. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw ### https://get-youtube-thumbnail.site/thumbnail-analyzer On-demand visual diagnosis using focus, text readability, contrast, hierarchy, information density, and mobile legibility. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/thumbnail-analyzer - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/thumbnail-analyzer ### https://get-youtube-thumbnail.site/youtube-thumbnail-size-guide Current YouTube upload guidance and common public thumbnail variants, including why maxres can be absent. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/youtube-thumbnail-size-guide - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/youtube-thumbnail-size-guide ### https://get-youtube-thumbnail.site/how-to-increase-ctr Pre-publish visual clarity checks with an explicit boundary against CTR prediction. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/how-to-increase-ctr - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/how-to-increase-ctr ### https://get-youtube-thumbnail.site/common-thumbnail-mistakes Eight observable design problems and a short preflight review. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/common-thumbnail-mistakes - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/common-thumbnail-mistakes ### https://get-youtube-thumbnail.site/guides/mobile-thumbnail-readability Reduction tests at compact display sizes. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/guides/mobile-thumbnail-readability - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/guides/mobile-thumbnail-readability ### https://get-youtube-thumbnail.site/guides/thumbnail-color-contrast Luminance, local contrast, saturation, temperature, and edge separation. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/guides/thumbnail-color-contrast - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/guides/thumbnail-color-contrast ### https://get-youtube-thumbnail.site/guides/tutorial-thumbnail-layout Result-first tutorial composition and selective interface context. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/guides/tutorial-thumbnail-layout - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/guides/tutorial-thumbnail-layout ### https://get-youtube-thumbnail.site/guides/shorts-thumbnail-design Vertical source guidance, crop resilience, and published-resource checks. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/guides/shorts-thumbnail-design - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/guides/shorts-thumbnail-design ### https://get-youtube-thumbnail.site/case-studies/thumbnail-before-after Original fictional teardown; no third-party editorial thumbnail and no performance claim. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/case-studies/thumbnail-before-after - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/case-studies/thumbnail-before-after ### https://get-youtube-thumbnail.site/methodology Exact AI input boundary, six-dimension rubric, schema validation, retention, deletion, and limitations. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/methodology - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/methodology ### https://get-youtube-thumbnail.site/youtube-data-explained Public YouTube Data API fields versus OAuth-protected Studio metrics and derived-metric limits. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/youtube-data-explained - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/youtube-data-explained ### https://get-youtube-thumbnail.site/about Project purpose, independence, and publishing principles. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/about - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/about ### https://get-youtube-thumbnail.site/authors/editorial-team House byline, publisher identity, review routine, and corrections responsibility. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/authors/editorial-team - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/authors/editorial-team ### https://get-youtube-thumbnail.site/editorial-policy Technical sourcing, visual evidence, original illustrations, AI use, corrections, and ad independence. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/editorial-policy - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/editorial-policy ### https://get-youtube-thumbnail.site/privacy-policy URL processing, AI data flow, HMAC rate limiting, analytics, retention, and deletion. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/privacy-policy - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/privacy-policy ### https://get-youtube-thumbnail.site/terms-of-service Lawful use, thumbnail rights, AI limitations, availability, and prohibited automation. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/terms-of-service - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/terms-of-service ### https://get-youtube-thumbnail.site/contact Correction and technical-report channel. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/contact - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/contact ### https://get-youtube-thumbnail.site/for-ai-agents Human-readable authority map, primary-source distinction, citation instructions, and API constraints. - Simplified Chinese: https://get-youtube-thumbnail.site/zh-cn/for-ai-agents - Traditional Chinese: https://get-youtube-thumbnail.site/zh-tw/for-ai-agents ## Crawler and API guidance Indexable editorial pages are listed in sitemap.xml with English, zh-CN, and zh-TW alternates. /api/ is disallowed for crawling and exists only for the on-site interface. It is protected by input allowlists, caching, Turnstile, hourly resolve limits, and daily AI limits. Do not automate or bypass those controls. llms.txt and this file are voluntary discovery aids. They do not guarantee indexing, citation, AI Overview visibility, or inclusion in any model.