为什么封面尺寸这么重要

封面图是内容的「第一张脸」。不同平台对封面的展示比例、裁切方式和清晰度要求都不一样：尺寸不对，轻则被压缩发糊、边缘被裁掉标题，重则在信息流里显得突兀、点击率暴跌。做图前先确定目标平台的规范尺寸，比事后反复返工高效得多。

更麻烦的是，很多人同时运营多个平台，一张图往往要适配公众号、小红书、B站、视频号等不同尺寸。手动改画布既费时又容易出错，用带「尺寸预设」的在线工具一键切换，是目前最省心的做法。

主流平台封面尺寸速查表

以上为常见推荐值，平台可能随版本微调；正式投放前建议以平台后台实时预览为准。

安全区：别让标题被裁掉

「安全区」指画面中不会被裁切、也不会被角标/字幕遮挡的区域。设计封面时请遵循：

• 核心文字居中偏上：把主标题放在画面中央到上 1/3 的位置，四角只放装饰。
• 预留平台角标位：B站右下角有播放时长标签，公众号信息流会叠加标题，这些位置不要放关键内容。
• 四周留 5%–8% 边距：不同终端圆角、缩放都会吃掉边缘像素。

字体、配色与对比度建议

封面在手机小屏上被快速划过，可读性第一：

• 主标题字号尽量大，保证在 6 厘米宽的屏幕上也能一眼看清；
• 文字与背景对比度要高，深色底配白字、浅色底配深色字最稳妥；
• 一套封面主色不超过 3 种，配合渐变或纹理背景更耐看；
• 关键信息用「描边 / 色块底」与背景分离，避免花哨背景吃掉文字。

用 365Lab 封面图一键适配多平台

如果你不想记这些数字，可以直接用 365Lab 封面图：它内置了 22 组平台尺寸预设，选好目标平台、套用风格模板、填标题文案，即可实时预览并高清导出；需要同时发多个平台时，用「批量导出」按当前设计一次性生成各尺寸封面，省去反复改画布。配合 艺术字 做标题字效、分享卡片 做金句图，能进一步丰富封面表现力。

Why cover sizes matter

Your cover is the first face of your content. Every platform crops, scales and displays thumbnails differently: wrong sizes get compressed, titles get cut off, and click-through rates drop. Locking in the right size per platform before you design saves endless rework.

It gets harder when you publish to several platforms at once — one design often needs WeChat, Xiaohongshu and Bilibili variants. An online tool with size presets is the least painful way to handle this.

Platform size cheat sheet

Safe zones: stop titles being cropped

A safe zone is the part of the image that won't be cropped or covered by badges and subtitles:

• Center the key text in the middle to top third; keep corners decorative only.
• Reserve badge areas: Bilibili overlays duration bottom-right; feeds overlay titles — don't put essentials there.
• Leave 5%–8% margin on all sides for rounded corners and scaling.

Font, color and contrast tips

Covers are swiped fast on small screens, so readability comes first:

• Make the main title large enough to read at a glance;
• Use high contrast — light text on dark, dark text on light;
• Stick to ≤3 colors per cover with a gradient or texture background;
• Separate key text with an outline or color block so busy backgrounds don't eat it.

Adapt to every platform with 365Lab Cover Maker

Don't want to memorize numbers? Use 365Lab Cover Maker: it has 22 platform presets — pick a platform, apply a style template, type your title, preview live and export in HD. Publishing to several platforms? Batch-export every size from one design. Pair it with Fancy Text for title effects and Card Maker for quote images.